I have no advice, but please post back here with how this turns out. I have not heard of bladder stones in dogs. But, if he can't urinate, I am sure that is an emergency. Keep us posted!
Yes it is very expensive to have the stones removed, but if they can hydropulse the ones blocking the urethra back into the bladder and leave the urinary catheter in, they might be able to get him to their regular vet in the am. Maybe not. They should still expect >$1000 bill.
The diet is probably the culprit. I've seen many a dog develop bladder stones while on Blue Buffalo.
I have seen bladder stones in a variety of dogs and cats, and they do also seem to be more prevalent in different areas... places with very hard water (high mineral content of water) seem to go with an increased incidence in the population from what I have personally seen in the various areas where I have practiced.
Diet/water source (I typically recommend bottled or filtered water depending on the area) or chronic urinary tract infections which can alter the urine pH are probably the most likely causes I have seeen of certain more common types of crystals and stones. They will know when they remove the stone and perform analysis on it. Certain breeds such as dalmations are prone to other types (urates, etc).
Often times bladder stones in dogs start out from an untreated bacterial urinary infection. The urine pH changes, stone develops allowing bacteria to populate the uneven surfaces of the stone, bacterial metabolites cause shift in pH in other direction and develops a second layer on top of the first stone layer, etc. Sometimes it is strictly a single stone type, others it is layers of usually two different types.
Diet change can sometimes get rid of the stone if it is a single type, but in cases of the "mixed" stones you never know which diet to feed to dissolve which layer of stone.
If this dog is showing clinical signs like vomiting and inability to urinate he needs medical/ surgical intervention. The by-products of body metabolism build up very quickly (eg. Urea, Creat) and make the dog even sicker.
The owners will most likely be in for an expensive vet bill depending on how sick the dog is and how many days will be needed on IV to get his blood levels down once the stones have been removed. He will need antibiotics and most likely a diet change pending the analysis of the stone to identify what the originating cause was in development.
I would recommend having the vet send a piece of the bladder wall away for culture and sensitivity testing to ensure correct antibiotic use as well.
