What to do for my grandfather and how do I help mom understand its time to take action?

my grandfather is 86, a very hard worker, doesn't like to ask for help and is running himself into the ground, he lives alone, works 4 days a week (which we all agree he shouldn't be doing) and his home is falling apart around him but refuses to move. we try to provide him with what we can to allow him to remain independent, but now its to a point I cant let it continue, for example his hot water heater went out months ago, causing the floor to rot when it leaked and now the floor is collapsing in in the kitchen, he heats water on the stove to take a bath and if we had the money to fix it we would, but we don't. He is heating his home via stove top, we freaked out when he told us that, and space heater, we have all noticed changes in his daily routine the past few weeks and small changes in his attitude. We also just found out he had a flat tire after work one night, the proceeded to walk half a mile to some random persons house to get help, he has a cell phone. Last night my mother, my self, and his lady friend couldn't get ahold of him, so in fear of something horrible having happened we drove out there to find out he had unplugged his home phone because he couldn't make it work, and cell phone was turned off. He is putting himself in precarious situations and there is so much more going on I cant explain it all on here, we need help and any ideas on where to begin would be greatly appreciated.