Have you thought about calling a suicide hot line? Or better yet, suggesting to him that he call?
The folks on the suicide hot line might have some suggestions. Also, at least in this state, there is a service through the county mental health facility where you can call and a social worker and a nurse come out and evaluate a person. Maybe you could check your county's web site to see if there are any mental health emergency services.
It is so hard to tell when someone talks about suicide. It can be a very real threat and it can be a manipulation. I'd say make a few calls, get some advice from a suicide hot line and after you've done what you can - pray.
I'll be praying that you find the resources you need.
God Bless.