For lack of a better word, it's not "natural" for a relative to easily believe that "one of their own" would molest/rape a child; matter of fact, generally it's the opposite (denial) when an accusation is made against another family member.
With that said; Why do you believe it's possible that your grandsons Joe and Tommy could have done this to HaLeigh - NOT INCLUDING ANYTHING THAT MISTY HAS CLAIMED/TOLD YOU/OR SAID. Have there been any past incidents of alleged molestation within the family that have gone unreported? Has anyone else (again, NOT INCLUDING MISTY) within the family ever claimed to have been molested by Joe or Tommy? Obviously I don't want you to divulge who specifically may have made these claims but I would like to know 1) If any such claims have been made and whether they have been made against Tommy, Joe, or both. 2) How many claims have been made and, if so, have they been made by one or more persons within the family?