Kitty really fucking hates Emma and in some timelines takes pleasure in killing her.
Emma and Jean are both omega level telepaths and that has had them bicker over who top bitch is in that regard as until Emma, Jean was the only other person than Xavier to be able to use Cerebro. So you can expect the other to try and one up each other in a possible relationship.
The only way for Kitty not to hate her guts is if she actually has to deal with Emma's family. Yes, they are that fucking bad. They are so bad that if her brother called me saying he did a bad thing I would start giving him advice on making it look like self-defense or getting rid of bodies.
EDIT: Frame of reference here: They brought back and made citizens out of war criminals, genocidal maniacs, Mystique, and actual fucking Nazis during Krakoa. But not Emma's sisters or father.
So Null can ask Jean to buy him some alcohol......
Why ask when you can just give her the money top grab beer and beverages for a movie night?