I would hate to see what you say about people who die from cancer.
Mental illness is a disease, just like cancer. It more often than not, has biochemical origins that is exasperated by traumas.
You wouldn't say someone who died from cancer they are a loser for the disease killing them. People with mental illnesses who take their own life are victims of a disease who finally overwhelmed them.
Mental illnesses have genetic components.
There are TBIs(traumatic brain injuries)
Acquired brain injuries
Anxiety/depression spectum
Substance/abuse-addiction
BUT at the end of the day, if a troubled individual isolates, and takes their own life with little warning, nobody else is to blame.
If people are concerned, suspcious about another person, say something, do something.