Few things to maybe chew on.Suicide is about the cruelest thing a person can do to their family, to the people they love and who love them. Only murder is worse. In the case of Cobain, he was infinitely cruel to his wife and daughter. She called him an "asshole" and a "fucker" at his eulogy. Understatements of the year.
1, He was massively depressed. Depression makes people act completely different when it's bad. I've seen it firsthand. It's not pretty. And, from what I understand, if it gets bad enough, suicide feels like the only way out.
2, he was a heroin addict- some of which was because he was in constant physical pain from an undiagnosed stomach condition.