That sucks the kid offed himself, but lets be honest, if someone wants to kill themselves, they will always find a way.
Sometimes, sometimes not. If you point somebody suicidal to real psychiatric help that takes them seriously, yes, it can help. Sometimes it will only help temporarily, and they will just postpone it until later, but sometimes temporarily is enough, and if you can get them over the bad patch, they can be turned around.
Giving them a tutorial in how to a whim into a plan, though, that doesn't help.