Definitely take him in for a check up for bladder stones.
Baby was a very good potty pan user, but he started peeing everywhere. I was baffled and thought that he had just turned into an indiscriminate pee-er.
When he died suddenly and unexpectedly, I had a necropsy performed. In addition to a tumor on his pancreas that had burst, Dr. Fitzgerald found several large bladder stones, which may have caused him to leak pee and he couldn't help it. I was not even aware that that could happen.
So now, any time a good potty pan used starts peeing all over, I recommend that they be seen by the vet.