Cats pee where they smell pee from before. I spent 3 years as a vet tech at a cat clinic and can tell you - just because you cleaned and can't smell the pee upstairs - unless u used a product to remove cat urine - he still smells it. Check the local pet store for odo-ban or a product designed to remove cat urine. Even bleach is not guaranteed.
Cats are weird. If he pees outside box even when clean see the vet. If he has a UTI he'll associate the box with pain so therefore pees outside box. Instead of using a large cat pan full of litter use one with a small amount you can scoop daily and replace all liter weekly. Tell DD scoop daily or cat goes. Many cats will not use a dirty box. We don't want to step in urine to pee why would they.
All else fails and he continues to terrorize the other cats then you're dealing with an aggression problem and can get meds from vet. I know people hate giving cats a pill but there are teansdermals which are in a gel like form and you rub into the ear and are absorbed. Kinda like kitty prozac. Hope this helps. My DD moved in with me a year ago and her cat still hisses and spits at my 18 yr old munchkin cat. Isolating her to the bathroom helps cause I think she feels punished, like a time out.