I want to die
I was thinking Death Drive. It's a Freudian concept thought to be the opposite of life instinct. There has been written quite a lot about it. Even in modern scholarly articles.
Your friend may or may not be depressed. If he had a depression on an early age, maybe a family member died around when he was 14, he actually may have built up some immunity to depression. Yes, that's possible. Around that age your brain and thoughts (e.g. coping mechanisms) are quite flexible, and all kind of changes both structurally and cognitively may happen to dampen hormonal depression. If that were the case, he may have suicidal thoughts without actually being depressed.
Secondly, he could be a perfectionist. If he feels incapable in living his life to his full potential, feeling he's never going to do what he should do, it means there is no purpose in his life. Psychologically the feeling of purpose is important for motivation and subjective well-being.
Irrecoverable loss: He has lost more than 90% of his capital. He feels he can never get it back in his entire life, or just doesn't want to any more. He feels his life might as well stop. He could have had the best life doing whatever he wanted, but he did not make the choice. This might lead to cognitive dissonance where his thoughts are adjusting according to his behavior. So, he thinks "I don't want to live" simply because his actions are like that. This is the same for a person who's not having offspring (or not intending to have a sexual partner). From his actions he may conclude he does not want to exist (i.e. his genes). Hence, death drive.
But I think it's also a combination of factors. Personally, I feel that death drive comes from a mixture of negative emotions. The main emotion behind death drive would be anger, since it is the most destructive emotion. If nothing goes like he wants it to go, and he is angry at has environment for obstructing him or angry at himself for procrastinating and self-handcapping, if he cannot externalize this anger rationally, there is only one way left.
I think you should really worry when he starts gambling, drinking lots of alcohol, auto-mutilate (look at his wrists or ankles), or perform other destructive behaviors. Family members doing one of those things also increases to chance of self-destructive behavior. It can be both genetic and 'virally' transmitted.
I would like to conclude with the knowledge from the field of psychology that humans are far from rational beings.
Next time your friend says
I want die
You can respond with
You don't want to live the life your living now.