What should a American mother do?

What should a American mother do? her US born daughter was abducted to Europe by her European father when she was a baby and the mother has not heard any thing from her daughter until she is 18. When she is 18 she went to the US embassy and asked them to help locate her American mother. She says that she wants to live in Europe for the rest of her live because her European daddy needs her and says that he is the best daddy she could ever have had. She wants her American mother to visit her in Europe. She says that as long her her daddy is facing criminal charges for not pay child support and parental abduction she can't visit the USA. Her mother also has to file paperwork in US court that she forgives the child support her daddy owes her mother. Other wise her daddy can't get a US passport. She and her daddy are citizens of Greece and the USA and have a valid Greek passport. She speaks Greek and no English and will need a interpreter to communicate with her American mother. Greece will not extradite her father to the USA.