How about you stop using your hair system and start using hair fibers. People will think you got a shorter haircut. WIll that work for you ?
It really depends how much "peach fuzz" or hair he has under the system and it's likely he shaved that to make the system attach better. I used fibers for literally close to 20 years because I had just enough of that on my Norwood 5-6 scalp to make it look alright if I kept my side bio hair buzzed. I also used a lot of Rogaine which may have helped kept that. But I've been wearing for a year now and obviously don't use the minoxidil anymore and when I go every 2-4 weeks to the salon for reattach, I've noticed the last few months none of that "fuzzy hair" is there anymore (not sure if due to the pressure of the unit always on top of it or an effect of the lack of using Rogaine anymore).
So that may not work for him as an option.