Allow me to add a fact: the suicide rate for whites (teens or total adults, whichever way you want to measure it) has ALWAYS been significantly higher than for blacks (you can look it up).
Suicide certainly has its environmental component, but depression is a bad disease and genes are important in determining who gets depressed and who doesn't.
I am truly sorry about your friend.
I've met black people who could have done with some very good therapy. The people around them tell them OUR PEOPLE don't therapy, that's for white people and look at all black people have had to deal with. Some people don't understand depression at all, and once I read MLK's son say that black folks don't committ suicide which is such a tragically ignorant thing to say. It's the black community's dirty little secret as Essence Magazine said last year. So if a young black person is surrounded by the ignorant who think getting therapy is acting white, or don't tell your business to a white therapist, well that person will only get more depressed.