Change his food to low ash cat food. You might have to see a vet to get the blockage removed.
blockage removed.
Our Bacci Vigna(just turned 15) about 10 years ago was straining to pee. Anyway, he had to have the blockage removed and has been fine. I have tried it all with cat food, made my own for awhile too but working person not convenient! Low ash maintained him.
God knowing, Cat loving individuals! My kinda place...(yes I am a nerd too!) But cant wait to get home today my boys my boys!