Here are thoughts that make me feel worse:
--Poor him, being all alone and having to go through this. Everyone deserves a support system.
--At least when I was helping/in contact he wasn't attempting suicide. What if he dies? Will it be my fault in some way?
--Do I want him to die without having said a proper goodbye? Without his daughter doing so?
You can answer each of those thoughts with the thoughts you posted right above it. You have given your best and he refuses to do the hard work necessary to get better. That is what it all boils down to. He refuses to do the hard work. He'd rather take the easy way out (and yes, it is the easy way to HIM) hoping you'll feel sorry enough for him to buckle under the pressure.
Why did he call you? Could it be that he feels you are his best hope to swoop in and take care of him? It's really amazing that even when they are practically at death's door, they still try to manipulate.