I don't want to get my sister a Christmas present

So, my relationship with my younger sister (she's 22 and I'm 25) has never been great but recently it's been an absolute nightmare. The last time she texted me was on my 23rd birthday asking to borrow my ID so she could get into a bar, and the last time we spoke in person she told me to "F*ck off." My parents have always tried to push us together and force us to have a relationship, but it just doesn't seem to be in the cards for us. We're all getting together for Christmas this year and it's expected that we all get each other gifts, but I really don't want to get anything for my sister. She has a 6-year-old daughter, so I'm thinking I'll get them a gift that they can enjoy together as a compromise, but it still makes me a little salty to get her anything at all.

Wedding present a free vacation?

We flew my SIL and her fiancee across country to meet him before their wedding. Plane tickets, guest bedroom, tours of fun places around our home, and took them to wine country for the day. Can we skip a wedding gift?