Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
I am very sorry to hear about Pepper's situation. If he is struggling to enjoy life as he once did, then we do have to consider his situation with great care.
Now if he is losing mobility and is generally uncomfortable (in his legs, bladder, etc), then we'd want to consider a trial on dog safe pain relief (ie Metacam, Onsior, Previcox
, Tramadol, etc) for him if you have not already. This could reduce inflammation at all his problem sites to help get him at least feeling more comfortable, like himself and allow him to once again enjoy life.
Of course, if we tried that but found it was not enough or those stones were causing him urinary issues (ie bleeding
, blockages), then we'd have to consider letting him go. But before we do that it'd be advisable to make sure that his withdrawing isn't due to a discomfort that we can address for him.
Please take care,