[PP]

Are the rules the same for FIBA or Federation? not sure
Player A1 drives to the hoop for a layup and begins his steps as B1 reaches in and fouls him. B2 comes from the help side and attempts to block the layup and in doing so, his momentum takes him into A1 and they collide hard into the mat.
The referee calls a personal foul on B1.
Is this correct?
Could the official call a personal on B1 and an unsporting on B2?