Re-laminate? Probably not. If you can live with the taffeta coming off, then do so. But lets be real, you have a sail that's 20 years old and it still has a good racing shape? You gotta post some pics. Close hauled looking up the center of the foot to the head.
20 years and now it's just starting to delam? Play the lotto. I've seen sails 5-7 years newer completely fall apart w/ moderate use, you can hardle ask dacron to last 20 years with shape.
Merit 25 # 764 "Audrey"