SS + GOMAD
No, but I think the solution is simple. He should just do the program, if he can't squat you have him use the leg press until he can squat the bar. Mobility is probably not the problem here, he just needs to get stronger.
Find a weight he can use with good form and without pain and go up from there, you didn't mention his stats but being conservative with the increases probably wouldn't hurt considering the situation.