From his specs it appears he's staying in the thumb too long thru the rotation - 1 1/8" up coordinate and 70 degrees of rotation
Does his wrist break at the bottom or his elbow follow the hand?

The most logical way for an up coordinate that much with that type of rotation is the hand being on the side of the ball at release
1/4 forward is a slowing release angle

Don't know Mo's philosophy only what a hand requires to release the ball properly
What's his ring finger span? What's his thumb and finger laterals?

What's his thumb lateral?

To me those specs and not knowing his flexibility or anatomy but those angles are keeping him in the ball too long thru the rotation in my opinion

please let us know what you adjust and how it works out.

I know for me, going more right in the thumb(right handed) really increased my tilt and lowered my track. Just did the same thing for my dad and he went from 3 degrees to 12 degrees. Some say it locks you in but if it is what your hand needs it seems to work.. I'm 3/4 right and clear the thumb fine.. Went from 1/8 to 3/8 right for my dad. Recheck his thumb lateral and see if he could stand to go a bit right..

Also is there a chance the span is a bit long?  I wouldn't think based on the thumb forward, but I know when my span was stretched I would come around the side of the ball and had very low tilt..

Maybe the ring is long..or the middle is too short?

Don't take any of this as gospel. Just throwing some ideas to maybe think about.