He did more than his share of mental and physical work up to his last years. And when he was close to the end, lying in our living room, his one regret at leaving this Earth plane was on watching me lug in the wood for our kitchen stove. He was a help unto the end. A month or two before he died he was sitting at table with us at a meal. I think I would do that too.
Animals know when to stop.
They go off in a corner and leave off food. I kept him full of liquids as often as he was thirsty. He got weaker, of course, and he was as gaunt and thin as Gandhi. From then on, for about ten days, he only had water. He was bed-ridden and had little strength but spoke with me daily.