Lizzie...For entirely different reasons, I have a regular nylon cat collar on Oscar, and twice a day, he gets a squirt of Feliway right on the collar. I squirt it slowly, I don't spray.

Might be an idea to try with Surya. It may calm him, and even help with his pee and poop issues - they might be behavioural, him trying to mark all of his scent EVERYWHERE.

He's a beautiful cat...so I hope something like this helps. Does he have his own water bowl? If so, Rescue Remedy might be another idea.

HUGS