Disgusting, criminal, manipulative behaviour by the mother.
Here is some case law from the UK.
"R. v Brennan [2007] 2 Cr.App.R.(S.) 50
Appellant convicted of abducting a son. He took steps to prevent contact between the child and his mother and eventually took the child to Canada. The judge described the appellant's behaviour as involving considerable dishonesty, planning and manipulations of the Canadian authorities and his new family in Canada. Eventually, the son was returned to this country. The appellant was deported from Canada and arrested on his return to the United Kingdom. Sentence of four years imprisonment."
Or R. v Kayani
Kayani took his children from the UK to Pakistan, after his marriage to a British woman broke down. The were removed in 2000 aged 5 and 4. They returned to the UK aged 17 and 16, refusing to meet their mother. He was sentenced to five years, the Court of Appeal saying
"The abduction of children from a loving parent is an offence of unspeakable cruelty to the loving parent and to the child or children, whatever they may later think of the parent from whom they have been estranged as a result of the abduction. It is a cruel offence even if the criminal responsible for it is the other parent.
These offences wholly achieved their intended purpose. The mothers have suffered extreme emotional hardship, and although the children themselves are unaware of it, they have been deprived of one of the foundations for a fulfilling life. The periods of abduction were prolonged, many years in duration, and the relationship with the mothers was irremediably damaged. In the case of the mothers, the hardship will be life long."
The mother here is a manipulative child abducter and should be facing a prison sentence.