transgender-Christmas problems

My sister is transgender (male to female) my parents are in denial. They say they are old school and just do not accept that this is a real thing. Anyway, she moved out. She was not an easy child to grow up with so our relationship is rocky. She was very disrespectful towards my parents growing up too. Anyway I'm home for Christmas with my two kids (we live 9 hours away) and she wants to meet up for a visit at my parents house. They said no. So we're going for coffee instead. I just feel so bad and I know my sister has some serious issues, she's very selfish and certainly not the nicest person..but common, it's Christmas. I feel like maybe if she had more accepting parents maybe she wouldn't be such a selfish nasty person..so I don't really blame her. I do try. I just wish my parents would try too.....I have a son and a daughter and there is NOTHING they could do to make me feel like that towards them. My love for my babies is unconditional. Has anyone else been through this? It's my daughters first Christmas and I really wish that we could all be together to enjoy it 😕😓