Cty 100 if your uncle just had surgery he might also want to look into a release aid called The Rip Shot it fastens to your elbow and hooks to your release and you pull with your back muscles .
Check out there web site
www.Ripshot.com you can hold your draw longer and even have a free hand for calling at full draw . I too have shoulder problems and i just won one on ebay and can't wait to get it i love the idea of not using my wrist and forarm . I have seen them in Keystone Country Store .com just trying to help ;-)