Your poor mum and her poor poor dog. That's just awful.

I would be going straight to the RSPCA and would be asking the vet to make a complaint too. As for the money side of it, TBH that would be the last thing on my mind and I doubt I would pursue it - there is no way I could "ask nicely" for money off the person who had effectively tortured a beloved pet to death - but I guess your mum could write them a letter at this point saying she will be seeking reimbursement from them so that that option is open for her to pursue.

I'm so sorry for your poor mum. I've got my boy booked in for a clip next week and although he and my parents' dogs have been there many times, I'm feeling sick about it.