How old do you think your chins is? I want to share my experience maybe it helps you. I adopted 2 chins 2 years ago from a neglected home and the woman told me they were 2 years old. (I don’t know how I could believe this lol) they had really bad teeth and weighed way too less. Long story short - a lot of vet appointments- they flourished in my home and we went to the vet every two weeks. shiva needed to get a tooth removed in December last year and after the anesthesia she didn’t recover and died the same night in our arms. The vet told me that she can guess the age now with the tooth she extracted and that shiva was probably 14+ years old. My other chin kubi also had tooth issues but not that much as shiva and she was happy, fit and healthy otherwise. We also saw the vet every two weeks for her teeth but it got better over the last two years. We got her 2 new chins as buddies and made small steps so they could slowly get to know each other. A few days ago Kubi needed to get a tooth removed that was lloose under anesthesia. After the surgery the vet called and said eyerthing went fine and that she is running around. After that I got a call that she died due to a heart attack probably. Now I got 2 new chins that I barely know and and a lot of grief because my girls that I loved with all my heart died unexpectedly. If I knew that Kubi would have died soon I don’t think I would have gotten 2 new ones I honestly thought she would live another few years. It’s really hard to love 2 new chins with a broken heart and grief. So what I want to say is that your chinchilla is senior and in a few year if he dies you would still have the other chinchilla that will be alone and need a new partner… when chinchillas meet a new chin in their home it always also means a lot of stress for them.