I don't know what the right thing to do is, but I know what I do--just feel miserable.
My elderly father seems, to me, to have clear depression and is wasting his life in front of the TV.
I have expressed my concern to both my father and my mother and they do nothing.
I don't really know what else there is to do.
You could tell him frankly, "FIL, it distresses me greatly to hear you talk like your life is over. I want you to be around for a LONG time. Could you PLEASE call this doctor and that doctor and do something to help your pain?" But if he doesn't do it, I don't know what else you can do. He's an adult.

FIL has always (since I've known him at least) been kind of morbid. I don't expect to change that. But now he's 81 and frankly, not doing great. He's in a lot of pain following a hip replacement surgery that seems to have gone poorly and at the moment has gout (that's been ongoing since he was much younger). Anyway, nothing that seems like it's going to kill him too soon. He's not taking pain medication though in what appears to be resignation to living out the rest of his life in absolute misery. It would almost be funny if it weren't true. MIL and Dh seem to be on board with his "plan" to just die soon, but it's driving me crazy to see him so uncomfortable. Has anyone dealt with an old grouch like this? He says he appreciates my concern (I researched some pain management centers in his area) but doesn't follow up. I know it's dh's responsibility but he's not the nosy, pushy type (like me!). And I also seem to be the only one who realized he might be with us for 10+ years more! WWYD in this position?