Docking clamps have very little shear strength, so I suspect if we just changed the decoupler into two docking clamps, your cockpit would fall off during the ascent.
It's a bit more complicated to replace decouplers with docking ports; decouplers just fire off of your current stage, and stick to the stage you might want to return to. That doesn't work so well when you want the decoupler to detach from BOTH stages, leaving the docking port free for later use.
So what you want is:
- A docking port on top of your fuel tanks.
- A decoupler on it, upside-down, so your lander detaches from your extra fuel.
- A decoupler on top of the other one, right side up, under your engine, that will fire both decouplers off of your lander, and into space somewhere.
- A docking port somewhere on your lander. On the nose, if possible. Anywhere else will require you to dock on your side, which will make controlling it more difficult.
Pictures of this will be forthcoming shortly.
This setup will allow you to take it back to Kerbin (if you have enough fuel remaining), and leave it in orbit for future use.
Kerbals can't die for any other reason than lithobraking (just like aerobraking, only difference is that you replace the atmosphere with the ground) and a collision with an object.
When you're in control of the command module, try switching to Neil by using the [ and ] keys. Unless there's a lot of debris near by, it should only switch between the module, flag and any kerbals on EVA.
If taking control of Neil doesn't work while you are in control of another object, you can go back to the space center and enter the tracking station. There you will be able to select your kerbal from the list on the left and press the "Fly" button.
The only thing that could prevent you from taking control of that poor kerbal is a bug.
In this case, basic troubleshooting. Reload your save file. If that fails, restart the game. If this fails, well, assume that Neil met the kraken.
You could also try bumping him so some of its variables in the code are changed.
If all fail, well, roleplay it. He died of hunger while you pressed the big red button in the tracking station.
Best Answer
You need to set the symmetry mode to 1 face only. You can do this either by clicking the symmetry icon until it shows one icon, or by pressing X (by default) until you cycle to 1 face only. The icon is the one shown in this picture, though it may looks slightly different due to mods/version