One thing you could try, put a plastic bag down in his (emptied of litter) box and see if he will go on that? The bathroom trash can size bags work well. A 12 gallon kitchen size would also do the job. Cats love poking around in plastic bags, maybe it would entice him.
One thing you could try, put a plastic bag down in his (emptied of litter) box and see if he will go on that? The bathroom trash can size bags work well. A 12 gallon kitchen size would also do the job. Cats love poking around in plastic bags, maybe it would entice him.