Jesus would not only go, he’d bring wine. Of course you should go, she’s your sister, a precious thing (especially to those of us who have lost sisters). You don’t have to approve, but you do need to love her and show her that love by being there for her. Don’t consider it aiding and abetting a sin, if that’s how you see it, consider it showing your sister that you love her no matter what.
No, he wouldn’t.
A vow to God is until death. Christ wouldn’t celebrate the sin of adultery.
Nah, He'd just make it when he got there.