I quit celebrating holidays long ago and life became much better for me. Christmas was always a particularly stressful time in my family, with some get-togethers ending in physical altercations between various members of the family while I melted into the background.
It's okay to say no. It's okay to tell your dad no. Nicely, politely and with love. If he thinks you're a party pooper, so what? Stay home, watch a movie, read a book, eat a cookie that you spent your last dime on.
Then one of these months when you have an extra five bucks, invite your dad for dinner. Sometimes it's best to not try to get the whole family together, especially when one person (your sister) has made it clear she doesn't want you in her house. Doesn't matter why, whether it's her fault or your fault or both of you combined. It's okay to tell your dad, "Sorry, not this year. Let's allow things to cool off." But do please remember to invite him over whenever you can to show him you love him.
But, oddly enough, given what I've already written ... I also agree 100% with Little Lulu. Christmas is one day a year. If your dad is getting on in years and if it's really important for him to have his family together on Christmas, it's also okay to suck it up, go in with a smile and to let whatever shade and tension your sis throws your way roll off your back like water off a duck.
One day a year ... for your dad ... who isn't getting any younger.
Whatever you decide to do will have some emotional repercussions because that's the way life is. Whatever you choose will take some real courage because both have some major drawbacks. I guess all a person can do is choose the one that has the least drawbacks and make the best of it.
I wish you the best, ForeverGirl, during this holiday season. I don't have a single light up and I won't. No special Xmas dinner. No presents given or received. My parents have been gone for many years. I don't regret making an effort to please my dad when he was in his 70s. After he passed, I started making "selfish" decisions. I did what was best for me and hang the rest of them. But while my dad was still alive, I'm glad I made the effort to grant him a few of his last wishes. After he passed, I was the only one in the family not reeling with guilt. I did what I could while he was still alive, even if it meant putting my ego aside.
Just something to think about. Hmmmmmmmm .... actually, I saw some Xmas scented candles at the dollar store and I might buy a couple of those. I like the smell of Xmas, even though I don't like any of the hoopla. What I like is being able to make my own choices. And I have a sister like that, too. So I kinda sorta know what you're going through. She's rejected me. It stung, but now I wish her well and pray for her happiness. Her actions stemmed from some deep unhappiness that I had nothing to do with and no power to correct or fix or make better. That's up to her. But I can wish her well and wish her happiness, all year long, not just at Xmas.
I guess I rambled on here, with a little semi-rant of my own. Take care, ForeverGirl. Please let us know what you decide to do and how it goes.