Your uncle is not suffering from PAWS after 10 years. In the worst cases, Post-acute withdrawal lasts only about two years after complete abstinence. Complete abstinence includes opioid and synthetic opioid pain meds as well as all benzodiazepine tranquilizers, among other drugs.
There are a number of other conditions with similar symptoms, including diabetes. He needs to discuss them with a good internist, and he needs to be totally up front with the doc about his history of drug use and his recovery.