I agree with the previous replies (unless his reasoning is medical then I disagree with the diaper comments lol).

Even if he has medical reasoning why he has urinary problems, he needs air to heal. If anything I would treat it like it is, a diaper rash, put some desitin oitment on it and lots of air.
Maybe she can build a kennel for him outside so he be out there sometimes and not have to worry about the diaper thing all the time.