Yep, there could be a problem with him having some kind of calcium defficiency or theres some weak bone disease/thing ive heard about. Maybe he should get checked out to see.
Or maybe, just maybe, he broke it without knowing like from a fall or something and the adrenalin pumping through him from the excitement of playing kept him going without knowing for a while(yes thats entirely possible).
Sounds a little stupid^^ But its still a possibility.
As for the PMR dispute I dont see how it can 'hurt' more than other markers.