Out of State Visitation

Son lives out of state and is court ordered to have his kids July 1st-31st. Divorce isn’t final yet so no order on how the kids are to get back and forth. My son has said he would return them, but is unable to get them. As the grandparent I offered to get the kids and take them to my son’s place so I can also see the kids. It’s a 1000 miles one way! As time is getting closer to July 1st all communication has stopped with her. She won’t respond to calls, tx messages, e-mails…nothing. I will have to travel 700 miles to get to North Carolina, and another 1000 miles to get to his place and I need to know she will comply. If my son has a document stating I have permission to pick the kids up can she deny me?? Killing my son no contact with his kids. What rights do we have in this situation. Lawyer said no agreement on travel plans nothing we can do. No separation agreement and divorce will occur in September. Help… I’m leaving on Thursday.
Thank you.

If there is a valid agreement that he have the children for those dates, the mother will have to make the children available to him. If she will not agree to turn the children over to you, he may have to make arrangements to get the children himself.