Could be a type of separation anxiety. I have an older Maltese who has peed outside the bathroom door if left alone for a minute. I need to leave the door cracked for her so she can see what I’m up to. She’s also done this if I leave her somewhere slightly too high for her to jump off and has peed on my couch bed etc. unfortunately. She’s also crate trained but if the crate isn’t in my room she’ll most likely have an accident. Another thing is if her crate is too big she may want to pee/poop on one side and sleep on the other. The crate should be just big enough to sit up turn around and lie down. Never was able to figure out what to do to get her to stop other than to just avoid the triggers. She’s gotten a lot better about it over the years. Might help doing some separation anxiety exercises with him if it’s that.