Animals generally don't soil their own sleeping, resting space. Keep him crate confined, take him out frequently to 'go' outside, then allow him to play a bit with the family in their space. Return him to the crate when you are thinking it's near time again, then take him outside again after a while.
Always crate for a bit following meals, then take him outside to 'go'. Lots of praise when he does, so watch for it.
He'll catch on quickly that going outside brings fun playtime inside with his people.
Jan in VA