I'm so glad that you add water to his food now!! That's such an important thing
One of the biggest pieces of advice the vets gave to me is that dogs with crystal/stone problems need to have access to a place to pee at all times. We use puppy pads for Miko to pee on so that he never has to hold it in. Holding urine is harmful to them particularly when they have bladder problems. So, try not to discourage him from peeing, but get him to pee in the right place. I know, easier said than done. LOL