I had a boyfriend with serious issues, PTSD from Iraq, diagnosed bi polar, many other issues as well. I told him once that if he threatened suicide I would call the police. He did, and I did. I pulled out the cell phone and got out the back door about the same time he pulled out the loaded .45. It was a 4 or 5 hour standoff before he came out of the house. It was awful, but it was also the catalyst for him to get the help he so desperately needed.
There is help out there for people who want help, and much of it is free for the taking.