HOw do i get my cat to stop peeing around the house?

We have a male cat, Cayman, and his sister, Meeka(yes both are fixed). Meeka has never once had an accident in the house, but repeatedly, Cayman has been going to the bathroom in the house. When he was a kitten(they are almost a year old so I guess they are still considered kittens) he had an accident weekly, and then he seemed to be doing ok. Then within the last month, we found out he was peeing on our dog(he's 7)'s dog bed, which Riley loves, and then the poor dog had to sleep in his cage(he loves his cage) without a bed. Then, we just found last night, that he peed all over the bathroom carpet right next to the bathtub. He must have been repeatedly doing this, because it smelled so bad in the bathroom and no one coudl figure out where it was coming from. My mom told me to investigate, and under the carpet, i twas soaked and it took an hour and a half to clean up the mess. Now Cayman is permanantley caged, and Meeka has free range. (she's a very good girl). The big problem is, is that Cayman is my little brother's cat, and he got him for christmas. If Cayman leaves our family, my brother is going to be devastated, so that cannot be an option. WHat in the world can i do to get this cat to stop peeing in our house? I've tried the pepper thing, and not often can i catch him doin git right at the moment, so it's almost impossible to spritz his paws when he's doing it. It's just a big mess and we will have to get rid of him if he keeps ruing the house.