Helping Children Come Home

My daughter,  her Dutch husband and my two Grandchildren moved to Holland to be with his family but after family trumoil they found themselves without a home and when to a shelter there, the family services told them that it would be better if they sheltered the children instead of the shelter they were in both parents agreed for their children, we have tried everything but haven't been able to get their children back that was in November of 2016, now my daughter has just given birth and the police has forceably taken the baby, my daughter is breastfeeding,  we have tried everything,  and  I am still in shock and don't know what to do,  so would also would like any information that we can do to get them back or how much i would need but the money would go for legal help and to get my grandchildren back to their parents and I would like to get them back to the United States as soon as possible, 

Thank you for just taking the time to read this