Genealogy photo retouching services: Younger version of elderly person

This is one of the pics we have of my great grandfather at 85 years of age. The only other photos are at about 45 years or younger. I need a photo of him at about 60-65 years. Having recently embarked on a genealogical study to recreate our family history, he is one of the people with an elaborate timeline. Is it possible to retouch this photograph (left) to make him look about 20 years younger. I don't expect this to fall under your free services, so please let me know how much it will cost."