Kelina Syn

The show is great I've been watching for years. Yet, I am still unable to keep my older male, Zish. (neutered when kitten) 10 yrs old refuses to poop, in the litter box, he prefers just outside the box...Please help! He shares with 5 yr old Lia (spayed since kitten) they both are very different. They get along until Lia wants to play and attack him he's much bigger. He is gentle though. Have even tried separate boxes.