If they can afford it, ACL surgery on dogs is highly successful. We had our dog’s acl done when she was 11 two years ago. Definitely extended her life-now if she makes it will turn 14 in June. 103 lbs is probably too much. Our dog was in the 90s. Now maintained at 65 lbs and much more mobile. I was against the surgery but given the result really happy we had it done.