My parents have an 11 year old golden retriever. His two back legs got real fat and swollen after bringing him back from a kennel. He’s been to the vet and on medication for it but it’s not getting better. To throw something else in the mix, they inherited a 1 year old boxer who is very playful. It seems like the golden retriever has a broken heart because he won’t get up when you call him anymore yet when he’s up he seems to be okay. What are your thoughts on this? How to cope?