That is a shame! If you can't get him help with legal aid let us know. I would be willing to chip in a few bucks. If the front casters are 10 inch I would pop for a pair that I manufacture with ball bearings instead of bushings.
In any case it wouldn't take but ten bucks a piece for a small number of the total people on the board to cover the repair cost.
Like what my grandfather said many times about some one like the guy that sold it to him. He should be set on a stump and have a spike drove thru his bag and then pushed over backwards.