It is so lovely when the disciple becomes the teacher! Tom know a few things or such! Thanks to him I have to healthy and happy torst!
I just read your post. Morla hasn't had any stones (yet!) but she doesn't drink really on her own and I was soaking her 2x daily when I first got her. It was her peeing brown one night that made me rush her to the vet and learn she was dangerously dehydrated (which can cause stones).
I'd get him to a vet asap, as they can not only help him pass it, but also test for kidney disease (what Morla has, due to bad diet and prolonged dehydration from the owners bf me), which can also contribute to stones because of calcium and urates not being filtered correctly (have vet do a metabolic panel blood test which tests calcium, urate, phospherous, protein, etc. In the blood).
Unfortunately, chronic kidney disease is incurable, but by identifying it as early as possible, you'll be aware. Then with relatively simple care steps, (watching hydration and keeping lowest protein intake possible), you can slow any progression and greatly prolong his life, if not simply prevent more stones.
Please get him to a vet asap, to get him tested for CKD/ any remaining stones asap, if not just get that present stone out. It's extremely painful and damaging for them!
Please keep us posted!!!