Well what do you want to do? Do you want to be supportive?
if someone wants to off themselves they are going to do it. no point in getting a bunch of other people involved. There's not really anything you can do for someone like that. They have to find their own new outlook and decide whether it's worth their time or effort anymore. I'd say the most you can do is drop by to see them every now and then to check up on them regardless of whether not you were invited, but don't make coming to see them about being suicide prevention. Try getting them to do things they enjoy even if its just eating take out watching tv.