Is there a vet hospital anywhere? You are in the Maritimes, right?

Not to nit-pick - but did they make sure poor Butter was grit-free the first time they sent him home?

Although - his bladder isn't enlarged or hard...so something is getting thru.

Try this - get some good cranberry capsules. Put about 1/5 of the powder in one of them in wet food, yogurt, pumpkin, whatever he might eat. That will make the urine more acidic and will help.

Also, get more water into him. Add warm water to his wet food...having anough bladder pressure might be enough to get the rest of the grit out. The pH food for urine will do this also, help dissolve stuff, and fairly quickly.

Please try to not panic (I know), and get lots of water into Butter.

Poor baby Butter!