I mean, that has to be it, doesn't it?
Sanji saved his crying ass, beat Yonji neg diff, Judge saw his strength when he hit Luffy using a power that he wasn't even supposed to have, everyone at Germa needed to play dirty against Sanji to get the upper hand against him, including Judge, and he still comes by the end of the arc to share the very same opinions he always had about Sanji
What else does Sanji needs to show to his siblings and Judge?