Explaining suicide to a teenager

One of my son's hockey teammates and friend committed suicide last week. My son has been spending a lot of time in his room because he's confused as to why and I had to go up to the school to complain because the football coach had said his friend killed himself because he didn't know God and that he's in hell. He didn't even coach this kid and knows nothing about him and that's disgusting to say to children. I don't know how to explain to him why and why people take their life.