Moving away from ExP

[PuddlePops]

Posting on behalf of my sister as she doesn't use MN.
My sister and her 3 y/o daughter live with our parents, and have done since 5 months into the pregnancy. My parents are now planning to move 2.5 hours away back to where they used to live as my father is retiring. They are keen for my sister and niece to go with them. My sister is happy to go, and my grandparents are a big part of nieces life.

She has told her ExP about the planned move, and told him about trains being regular so on, but he is saying he will take her to court if she moves, and that she will have to apply to get a council flat as it is breaking his contact order taking her that far away. He has a contact order for 7.30pm-next day 6.30pm once a week.

Would she be allowed to move, or could she be forced to find accommodation where she currently lives when our parents move?

My parents not my grandparents*

Will he be able to have contact as in the order? Would she be willing to travel with her DD to where her ex lives in order to fulfil the contact? Or cover his travel costs?

My understanding is that if the residential parent moves away despite the objections of the non-residential parent, the onus is on the RP to undertake the trouble and expense necessary to maintain the contact.

There's an order she's willing to break??