Polyframe Judge with PDX ammo used in SA mode. Also consider taking it to a smith to rework the hammer for more leverage to make it easier to cock and to also make the trigger easier to pull.
Never shot a Judge, and I understand that they are of good size, but wouldn’t this person’s hand and wrist weakness preclude anything with substantial recoil? Since he is already having problems with a 9mm, I would think this would almost automatically rule out a .45 colt/.410 shotgun combo.