Any fracture in the hand or wrist needs to be evaluated properly. You want to minimize the damage not create issues that are highly problematic even chronic. Say he has a navicular fracture. It might be minimal and non-displaced. You fail to recognize that injury and it fractures into two pieces you have a huge problem.
He can play in a soft cast even one covering a hard one. Might take a few weeks but that's better than big surgery and out for the year. Best let a hand surgeon take care of it and avoid jumping to conclusions.