My friend is engaged and she and her fiancé have custody of HIS 3 children ages 7,6,4. They have recently split up and she wants the kids. She has the means to care for them. He does not, no job, no house and no car. The kids' mother is also unfit, that is why the kids are not in her care. Is there anything that can be done?? Please help these innocent children. Thank You

First "she" did not have custody, I will assume her fiancé had custody, or at least the children were living with him,
Do you know if he had legal custody of the children ?

I guess both the mother and father could sign over guardianship of the children. But most likely as soon as he is back on his feet, he will then want them back

First, your friend does not have custody of the children. Becoming engaged to their father does not convey any parental rights to your friend.

If she wants the kids she can ask the former fiancée and the children's mother if she can be granted guardianship for the children with the intent to adopt.

But if the father or the mother refuses she has little recourse. Her next step would be to go to Family Services and ask that the parents be evaluated and tell them she is willing to foster the kids.