I've got an answer for your problem, which I will address first, and then something for you. Yay!

Group Effort

This is the one avenue it looks like you haven't taken. You know you haven't taken it, and it seems you're reluctant to do so. Likely because, even if you did get the others behind you, this person would act out, become sullen, and maybe increase the drama.

Talk to each one together or individually. Be honest about your intent, who you've talked with, and what you want to accomplish. Stress that if they can't work together to help even things out, you might have to end things. It's not worth suffering in your hobby, at least not this much. GMing is suffering enough, having to juggle the drama is not worth it.

This is the step you need to take, now, before you have to...

Kick Them Out

Let's go over what seems to be obvious from your question. It's obvious:

1. Your play styles don't mesh
2. Your standard approaches to these situations didn't work
3. Nobody is willing to do what needs to be done

Just because you are friends doesn't mean you should sacrifice your mutual fun and enjoyment in order to accommodate this person. It's perfectly reasonable to be in a situation where you all want to do thing, but one person doesn't want to do it the way the rest of you do. Trying to work around it is getting you nowhere and is ending up just costing you fun.

I don't mean that you have to be mean. But it sounds like the only way this is going to be fun is to part ways in this thing. I'm sure there are other things you can do together you find fun. I know, you said:

I can't really do because of the group of friends

But if you want the problem fixed, that's where you're at. Or, you can keep going with the status quo and keep hoping something changes. I know it's hard, but part of making sure this hobby remains an enjoyable one is taking the steps needed to weed out the things that are making it less enjoyable. I personally hate weeding, but dang it, the grass sure does look better.

Are you sure the player is the problem? This sounds like an issue that can be easily resolved by simply asking them.

But he is nonetheless disrupting other players by showing them his drawings (or they want to see it themselves). I have the feeling that it negatively impacts the immersion of the other players.

The first thing you need to do is ask the other players if they feel he is being disruptive with this behaviour. If they don't, then the problem isn't where you think it is.

From the outside, this sounds like you personally dislike the activity because you have a picture of how you think the group should be playing, and they're not fitting inside of this. This is fairly common when you're in the DM position. For instance, you want them to be taking something incredibly seriously, but the players are acting whimsical and unfocussed.

The bottom line is that this is meant to be a game played for fun. The most important question you need to ask yourself is, "Are the players having fun?"

If they answer is yes, then start evaluating why you are not having fun, and discuss this with the players to see if you can form a resolution. Ultimately, you can't make somebody stop drawing. You can ask them to. But primarily, you should be discussing it with the other players to get their opinion.