My Dad (85 Years Old) Had Open Heart Bypass Surgery

My dad (85 years old) had open heart bypass surgery a year and a half ago and he has been having hiccups off and on rather continuously since then. He has been prescribed a pill (I don't recall the name) which he takes 3 times a day - it is difficult to tell if it helps at all. He sees a neurologist for Parkinson's and an ENT for some symptoms associated with that disease. It feels like he has gotten the run around as to who can help him. We have heard of a possible agitated nerve and a surgical treatment, but never have talked to someone capable (or willing) to treat him. Any suggestions.