If you stand by people who are depressed, struggling and have their back against the wall, as soon as their lives are better and they feel good about life again (no longer depressed or desperate) – they will tell you your friendship was a waste of their valuable time, that you are a reminder of how bad they felt about themselves and they don't want that memory and then they will walk away and never bother to speak to you again.
Happened 3 times so far 🙁
Life lesson: Friendship for many people is only a concept, self is all.