father in prison 2 1/2 yrs out 5 mo seen kids about 20'xs. Hadn't tried to see them, they have asked 2x's to see him and he said no. he is drinking and doing drugs but doesn't want his mom to know so he lies and says he texts/call kids and they don't respond. He and his mom both say they don't want to anything to do with kids but now they want to see them at Christmas. Father's relative called to say the gmother is going to lay into them and tell them what horrible bratt kids they are because she believes her son. Kids now do not want to go at Christmas because of the adamosity (SP) between them & gmother. Dad lies to drink but doesn't want his mom to know truth so he lies about his kids. Do they have to go? Will I be in contempt, if they choose not to go?

You are the custodial parent and the father is attempting to enforce the terms of a custody & visitation order? He could perhaps claim that you somehow persuaded them to refuse to see him. So you should do everything you can to strongly encourage (i.e.: force) your children to see their father.

You don't mention if there is a court order for visitation. If there is you could be cited for contempt if you do not make the children available for the visitation.

If and only if, there is a court order and if and only if, that court order says he gets them for visits on that specific date.

I would have course call the mom up and explain things to her in real life, what is happening.