I had the same problem with Mina peeing on my fiance's side of the bed. We ended up putting her in a kennel with some Fresh Step Kitty litter in her box for a day, and she hasn't went anywhere but in the box since.

Is there a reason why Caleb can't have regular kitty food? I wasn't here when you got him apparently. It might work if you soften it for him if its too hard. (Not Mina she got ticked at me when I did that, and gave me that look like "I'm not a baby MOM!"

Keep us updated on how he is doing.