Does Giselle have siblings or step-siblings?

I’m trying to piece together who changed her father’s will. I maybe missed something in the earlier seasons - I assumed she was an only child. Does she have siblings or step-siblings or stepmom that she’s implying changed it?

Edit: it seems to be the general consensus that stepmom/Curtis’ wife was the one to change it. Very heartbreaking that the family has to go through this after losing their patriarch.