Your head pattern follows your knee bends,hip bends and your footwork.Through this he will become hard to hit and will create the correct angles while maintaining his prefered fighting distance. Get his head doing U shape ups and downs from leg movments so he practices moving his head from inside the guard the outside of the opponents guard looking for the openings and angles both gloves up at temples when in that close,body bent and sucked back knees bent and doing the work. Then bring his footwork in to the whole thing so he can create those devestaing angles from the outside wen you can really cut loose as the opposition adjusts.
So when youre shorter in reach and want the close in fight to suit your added lower centre of gravity and added leverage in shots off your legs ..then: you train for flexability in your joints, hips, knees especially ,stretches so you gain fluidity on the move ,get him to bend at the knees and train him to move out to the sides on angles so you introduce the footwork with the joint bends .Watch how Mike Tyson was origionally taught to do this and copy his every move.