I have 8 yr old kitty that always used litter box to poop until recently, now uses floor. (2mo) Took to vet, he is fine, vet said behavior issues but offered no solution. Uses box to pee. No changes in his or our routines. Very clean litter, no changes in box. Clean floor after he soils very good. He has always been very close to me and I have been under a lot of stress due to family health issues. (2mo) What can I do to get him back to using box? Please help, thanks in advance.