Like a kiddnapping

[Diane_123]

My husband's daughter was taken by the Mom when the daughter was 1 to Mexico without notice or any information 4 years ago.  They were in So. california at the time.  She has been located now in Mexico.  The daughter is american born, the Mom is illegal here in the states and the Dad has resident status. She has never provided in 4 years thier location.  She is now temporarily staying with my husband's family due to she was probably homeless and she called them, which she has never done before.  My husband wants her.  What can we do???