probably die of old age in your sleep.
Dying in your sleep, pretty sure every person would wanna go that way.
Regardless of what project you are doing this for, you really should have the foresight not to post this question online and to do your own research, you know young people turn to a site like this for help and there's inevitably someone who is going to get an idea from this. Death isn't easy nor is it painless, kids.
and then waking up from a 6 month coma, with brain damage?
I'm not tellin'!
-A brain stroke while you're sleeping. -A big boulder, an A-bomb or comet falling right on your head while you're sleeping. -A jump in Polar Sea when it's near freezing point might take a few seconds longer. -Being an Afghan when a drone passes might be painful. -An overdose of anything might let you alive but diminished when you get out of the coma. (I've known that to happen to a very young girl I knew well. She committed suicide a few weeks after getting out of the coma, when she realized what was gone and what was left. An awful story.
Yeah, pills or heroin/morphine...
and then waking up from a 6 month coma, with severe brain damage?
i'd go for a heroin od