ISAAC.
You're allowed to be an authority figure; you're an adult and she's a child.
Look, I see where you're coming from, but newsflash: this is my house. Not Allison's. Not Joey's. Not LA Isaac's. Mine. And if you want to come, then I absolutely want you here. If you don't want to, then that's all right and I get it, but don't make it about them. It's about you. They'll get over it. It's one day.