I'm in need of advice about my friend.

For you too understand you'll need a bit of context.
I have two male friends. We'll call them J and L.
J is dating this girl, we'll call C.
L use to be C's ex.
The other day supposedly (according to C) L kissed her.
Now J hates L and is spreading the rumour of this kiss.
My friend L is really down low and in need of a friend and I'm trying to be there but I don't know what to do.
I think he feels suicidal.
Do I tell someone else for help or try to keep it between me and him? I am no therapist after all.

Hello Fenrir. I do not think the incident is behind your friend's suicidal emotions. He perhaps already has a vulnerable background which is easily triggered upon sad incidents. If you do see any suicidal signs on any person, it is always a good idea to let a professional or a a grown-up know about it, because they might need a serious help. It might be that you're over worried and analyzing, however, even a poor sign is worth of being taken into consideration.

Much appreciated your reply, I might be over worried, like I said I'm no therapist.