Partners children abducted by mother - breaching a court order

[alzacm]

My partner has 2 children and has joint custody of them via a court order. We went to pick them up from school yesterday and they are with him from thursdays to sundays and were told by the school they weren't there and the school didn't know where they were. We tried contacting the mother and his son, both phones are either blocked or turned off. The police refused to help and would not tell him any more than that the children were safe and well. Eventually we were able to get the mothers solicitor to tell us that she has raised concerns of abuse against the children with social services and police and they are in support of her temporarily leaving her home with the children to protect them. No one will tell us what the allegations are, we've had no contact or response from social services or her solicitor. Any claims she is possibly making of abuse are untrue, and there is certainly not a significant enough risk to the children's safety to breach the court order and cut off all contact with him. What on earth do we do. We can't afford a solicitor