Sole responsibility

I am kindly asking a question

A family member recently go custody of her two children. She has been here for a few years on a health and social care visa. The children were previously refused a visa as the other parent was not able to come. They are unfortunately now divorced. That father relinquished care of the children as he said he did not want to do this anymore. The children are with the wife's family. His family also refused to care for the children siting that if the mother is abroad they don't feel responsible for this. The custody papers have given him school holiday contact. Sue keeps in touch with children everyday online and does homework with them. She travels home three times a year. Her family manage the practical care but under her instructions eg what activities kids do, if they go to the doctor's or dentist, what school trip they attend
What are the chances of her being able to bring her kids to the UK, many thanks

See also Sole responsibility. If the parents are divorced, then there should be no expectations of the divorced father, who has no responsibility, joining the children. The mother should show that she makes all the decisions for her children.