I have diagnosed pf in both feet and my pain is in the outside of my foot up near the ball of my feet. Not saying its his problem, just pointing out it can be in other areas of the foot. Properly fitting support for the arch correct shoes are the best thing you can do for your feet.
Also streching your feet while sitting can be a big help. A chunk of pool noodle wraped in duct tape or 12" of wooden dowling ( I would find broom stick or closet rod size.) Put it under your bare foot and roll it back and forth while adding lite to strong pressure can help any foot recover or just stay heathy.