Freaky!
J/K ... I have that to some degree too ... not sure what it is ... it doesn't hurt so I don't worry about it! (Also if you saw the size of my feet/ankles during my first pregnancy you'd understand!!)
Could be some micro-tears in the fascia I guess ...
The pain is something else entirely ... feeling like the bottom of his feet are on fire is not normal and honestly probably not related to those bumps. Sounds like either a plantar fasciitis (which maybe it isn't since it sounds like he's been treated for that without success) ... or it could be something with the nerve (adhesions causing impaired mobility ... burning tends to be a nerve-type pain, but not always) ... or it could be referred pain from the subtalar joint (in which case it would respond to some good joint mobilizations, usually into eversion, grade III+ or so ... )