Delicate Situations

It's been brought to my attention by a good friend that life is tough and there are going to be times where you can't help everyone. I've bumped into a few situations myself, and I'm sure many others have gone through it as well.
There is a high percentage of suicides. Mostly, adolescent suicides. Growing up I never thought I'd be friends with suicidal people. Well, I was, and it is a traumatizing moment in my life. I was the same age as them, how would I know what to do? I didn't see any sense in going to an adult because that means breaking my friends' trust in me to keep a secret. It killed me a little more inside every time they'd slash at their skin or threatened to take their lives.
I'd rather not indulge into the subject because it still pains me to think about it. Long story short, I decided not to interact with these "friends" any longer. They hurt me once, I chose to disallow them from hurting me twice.
This was just an adolescent attempt at suicide (or most likely attention), but what about adult suicides? There have been a lot of different stories where adults feel the need to kill themselves and their children in order to prevent anymore downfall. It's a hard time, I truly understand that, but taking the lives of your kids and the yourself? That I find highly immature. "Desperate times call for desperate measures." Desperate measures not taking lives. Lives, as I have stated in a prior post, is too valuable and too delicate.
My friend (let's call him Bobby) had a friend (let that settle in) and Bobby tells me that his friend's parent chose to take his life leaving this friend behind. This friend is our age, I don't know what to do and neither does Bobby. This is a fragile topic and a delicate situation that I cannot unscramble. Given the chance, I would take Bobby's friend into my life in a heartbeat, but I don't know how to take it. How do I handle this situation?
Keep in mind, I'm not the most experienced. I guess all there's left to do is pray.