Finance and children access after being divorced

I need some advise on behalf of my little brother who is at his wits end, my brother got divorced numerous years ago, he has his children almost every w/e Friday to Sunday, 1. this Valentines he told the ex 4 weeks notice that he couldn''t have the kids on Valentines w/e as he had made plans, obviously ex ignored this and kicked up a stink, knock on affect she has stopped him from seeing the kids completely, stopped all contact for him, blocked his numbers and top of that stopped all contact for his family, basically none of us can get in touch with the children......what is the best course of action to take here?

2. Contesting the Absolute relief agreed during divorce(2+ years ago), as not in right state of mind, ex minuplated my little brother in signing everything over, he didn''t even want the divorced, he just did right by the kids on his vunderabilty, is there anything he can do to get some share of the equity on there ex marital house, baring in mind he paid everything for the 10 yrs they were married she contributed nothing.

Much appreciate any advice and help given, as a big sis I am worried for my little brother.

I can''t advise with the first point but I expect it will be a case of gaining access through the Court system if all else fails.

As for point 2 - you say that he ''signed everything over''. Was there a Court Order or a Consent Order? If not, then the doors are wide open for negotiation but, if there are still children of school age then the wife and their housing needs will take priority - it matters not a jot that he paid everything for ten years.