Hndaifi, I think you know I do not believe in gods, therefore I do not believe anyone burns in hell or blazes. That may not comfort you, I know, but consider the possibility.
It is very sad when a young person passes, no matter the reason. However I once had a young friend who refused treatment for very advanced cancer. sometimes a person is in great pain. Whether it is physical or mental, it is their choice. We never understand, we feel angry and often we feel guilty too. One thing we can do is respect the deceased's decision.