Not exactly the same situation but I have a neighbor your age that's in about the same physical situation but still works. His back grows completely wild. I'm older and retired but in better shape and have no problem with this as I have bushes and trees on my side and just trim as necessary. We get along fine. A few years ago he had a tree fall into my back yard in the winter and I called and told them since they probably could not see it from the house. They got a son to remove it and I discovered later that they probably did not have to do this as it was an act of God on my property. Point is you don't want to fight with neighbor. Maybe he'll loan you truck to cart of debris.