It's still warm and winter has not arrived so we don't have much
choice than to leave him outside when we are away. The neigbour is not
going to want to change his dirt box once or twice a day.


IMO, with an elderly cat with multiple medical problems, I would not
want to leave him outside while you are away. I would hire a petsitter
(with medical experience!) or board him at the vets to make sure he
gets the care he needs.

Rene