I totally would not have expected that kind of damage from a hip/leg shot. Ouch. Hopefully it doesn't get worse.
Virginia,
From the description given in the OP, it sounds as if the bullet travel/direction was into the hip and towards (directional to) the other hip. Thus more damage internally, to everything in between. (So the congressman's side was facing the shooter.)
There may have been less damage, if for example the victim was standing straight and facing the shooter, when the shot was taken to the hip.