I am DMing a game where one player has never quite seemed happy. He regularly questions rulings and gets quite hurt when he tries to do things with his character and they don't succeed.
He is playing an Elf Rogue / Hexblade Warlock, but consistently tries to play the character like a tank, running to the front and attacking before any other party members. Many of the encounters I design have a high (difficult or near deadly) CR but include puzzle elements to allow the party to win them either by achieving their goal without killing all of the opponents or by using the environment to their advantage (one was designed to give them an advantage in pushing opponents off of a high ledge, another included grease bombs that they could set on fire). He has also died when facing large numbers of weak opponents, for the same reason (he runs into combat and winds up surrounded).
For clarity, every one of these encounters is designed to be winnable by the party, and all other party members regularly get through them, including an incredibly squishy wizard. The CR is set high because they have other things working in their favor (the ability to push enemies off the edge, for instance). I also typically provide a way for the party to save someone if they get into trouble (i.e., if one of the party members inadvertently falls off the edge, they'll get several opportunities to save and catch hold of something).
While the rest of the party tends to squeak through these encounters and have fun while they're doing it, he has died five times. For example, in the case of the party fighting a few powerful enemies along the ledge, he had the option to Hex enemies for STR, granting the party an advantage when trying to push them over the edge. Instead of supporting in this way, he ran to the front of the group — ahead of the two tanks — and attacked the lead enemy. Since he had no allies around him, he also did not benefit from Sneak Attack. He seems to have optimized his character for one very specific combat scenario, without ever telling me what he expects that to be or being prepared to encounter anything different.
At each death I've come up with a way to revive or reincarnate his character, but he is still upset. I have given him numerous opportunities to roll a new character that fits his play style, but he has rejected them. I obviously cannot tell him how to play his character, but I'm at a loss for how to make the game feel fun for him, as well as the rest of the party that seems to enjoy it as is.
After our third session, I sent out a very detailed survey to the party members asking them about what types of combat they preferred, NPC interactions, puzzles, etc., and the party seemed to enjoy this type of game play. This particular player was an outlier and asked for a more "sandbox" type of game, but also requested that they receive more clearly defined goals and quests / jobs (clearly these two things are incompatible). In general, I have opted to provide clearer goals while deliberately creating multiple paths to achieving them (combat, NPC interactions, puzzles/sneaking/heists).
When I have tried to guide his character and the party more closely, he has complained about railroading. I've included friendly NPCs in combat situations to demonstrate how the environment can be used tactically, have used NPCs to make tactical suggestions, (he complained about NPCs in combat and said he didn't like it), and have tailor-made a deep backstory and NPCs to explain his character's "recklessness" and repeated reincarnation. We've had discussions about the death of characters being just part of the game, and it being something he can have fun with, if he wants to incorporate it into his play style. I've even created a demon who visits him whenever he has a near death experience. None of it works, and he always winds up upset when his character dies, or is even incapacitated.
He does very little roleplaying and instead focuses almost exclusively on his stats and abilities. Put differently, how do I engage a player who is playing his character poorly?
Addendum: Thanks everyone for the fantastic answers to this! To put a button on this, after multiple conversations with the player in question, it turned out to be a combination of several of these issues. There was definitely an element of "My Guy" syndrome.
He also really wanted a totally sandbox game, as opposed to the more structured, quest-based game the other players in the party had requested.
Lastly, and most tellingly, he admitted that his interest in playing was primarily to experience a power fantasy. Obviously anything getting in the way of that, such as character death or any real consequences of any kind, are ultimately unsatisfying if that's the case. He's decided to step away from the game, but no feelings were hurt, so it was a good resolution at the end of the day.
Best Answer
Give 'em enough rope, lose the safety net
This character is being enabled to fail by the DM, you, even with the best of intentions. You'd like for the player to enjoy a character concept that he's come up with. The problem is that his play style is suicidal, and as you note (1) his PC dies frequently, and (2) the rest of the players "get" team play far better than this player does.
You have tried coaching and counselling (Well done! I've discovered that coaching is a part of the DM role). At this point it is no longer your problem to solve: it is his problem, and - this is important - the party's problem to solve. The rest of the players have been carrying this player and his suicidal style.
Next time the PC dies, ask the surviving party members their plan
This next time, it looks like there will be no "repeated reincarnation".
This puts the burdeon on the party as a whole to deal with a dead character.
Address them as characters and ask them:
What is your plan for getting {this PC} resurrected/raised/reincarnated?
If they don't have one, he gets to roll up / create another character whom they'll meet soon during the next encounter.
If they do have one (perhaps paying for that reincarnation spell) let the dynamic between the players - your problem player and the rest of the group - play out. For example: it may be that he needs to carry his own diamond for revivify (if your party has a cleric).
At level 5, if the party cleric needs to keep a slot for revivify always prepared (thanks to this PC's suicidal style) I know that a condition I'd consider as a cleric player is something like this: "your character needs to always have a 300 GP diamond on his/her person. I'll need it to revivify you if you expect me to bail you out yet again."
Not sure how your other players view this, but that's one way to marry up the in-game and out-of-game communication at the table.
Choices have consequences
You mention that this player gets upset if they get incapacitated. That tells me that this player does not actually understand this edition's mechanics. Dropping to 0 HP and having an ally pop you back up (or getting that lucky death saving throw of a 20) is a part of this edition. (Some people call it yo-yo healing and don't care for it, but it's a part of the mechanics).
This player may be a slow learner, who also seems to not understand team tactics. This is not uncommon; I've seen that manifest in various ways over the years. If the character keeps choosing to behave as a fragile tank, the consequences are that the PC will often be dropped to 0 HP or die. The former is no big deal, with this edition's recovery mechanics. The latter is a bigger deal for both the player and the team.
Until the player accepts that, I don't think you'll see a change in behavior. In my experience across numerous editions, enabling play that does not fit what the team is doing is counterproductive in nearly every case.
Your last bit of advice to this player: be a better teammate
You can offer some general advice along the lines of
The point of emphasis ought to be on teamwork.
You mention in a comment that
That's not teamwork, and it also an added burden on the DM. Make sure that you tell him that his behavior is making your job as DM more difficult. (One of a number of fine Q&A on dealing with split parties - there are a bunch of good inputs here on how to deal with this if it keeps coming up).
If he chooses to fit into the team approach to the adventures better, his PC will either stop dying or die less often. There's a lot of room for being 'down but not out' in this edition. Older editions were a lot more lethal in terms of "you are dead, make a new PC" than this edition.