AvatarNathan Richer

try these to start:

there are a ton of videos out there. do you have a PRO account? some more behind the paywall.
also i would not rule out resetting the femurs to the rear of the hip joints, using banded distractions, and also examining his external rotation.  smash also the adductors on the insides of the legs, check hams, quads, glutes, TFL.