What Achilles had gained from both his parents was pride. Peleus was stomping on old grounds and Achilles too offense. How dare he come back around, throw himself in his life and put Achilles in this giant storm with his mother as if he were in some custody battle he wasn't allowed to have a say so in. Grown or not, Achilles was the child between them.
"Then he's not welcome here." Achilles scooted his chair back, that look on his face that only a warrior knew. It meant this could end very unpleasantly.