Start at the foundations; become flexable and mobile, sit down and do the splits, slow stretches then get your head down to your knee while you hold the stretch,lay down on your leg. and do slow stretching squats too. Standing ,hold your heels and pull down so your head touches knees etc.
To break it up ..Basket ball moves help alot and tranfer to the ring well, table tennis too, anythng that involves hand eye coordination and continual movment with joints bent .
This will lossen you up so you can bend low and then introduce footwork so you can move low and stay (on balance) while weaving around and going under shots, yet still looking up hunting for the openings and evading at the same time. Practice in stages then bring them al together for him.