I would definitely go. It’s your nephew. He’s family. Related by blood. If I was to boycott everyone I don’t agree with...well...
My best friend turned out to be a lesbian when we were teenagers, should I forsake her? No way!
Hi Susanna!
So, if you were to go to your best friend's wedding, would you hug her and congratulate her and her wife, knowing that according to God's word that anyone who is living that life style will not inherit the kingdom of God? How could you be happy for her knowing where that life style leads?
"Although they know God’s righteous decree that those who do such things (men with men and woman with women) are worthy of death, they not only continue to do these things,
but also approve of those who practice them."
As the scripture above states, would you not be one who is approving of your friend who is practicing this?
If I was in this situation, I would take the opportunity to make known the severity of her sin, that as long as she willfully remains in that state, it keeps her separated from God and on her way to condemning judgment. That's guaranteed! And you would be helping her to get there by supporting her.
If I was RickyZ, I would see about setting up a time to speak with his cousin before his wedding and lay it all out. I would make it known that he has the right to continue living a same-sex life style, however the consequences are the same.
This eternity we're talking about! To not tell them and to support those living that life style, is to not love them, but to help them on their way.