custody law question

[murdoc94]

Hey guys and girls, it has been a while since I posted on this board but here is my problem:
American male brought over Ukrainian female and two children to the USA 3 years ago, he maried the mother of the children. The oldest child is 18, the other is 15. Both parents are very harsh on their children but do not physically abuse them, just constant yelling/fighting. The father (american) always threatens the 18 year old that he will send her back if she does anything he doesnt like. Here is the question, since she is still waiting for her green card, what type of custody does he have over her? I am assuming he is talking about deporting her back the the ukraine alone. I would think when she is 18 he would not have the possibility to do that without her breaking the law or something extreme like that. If anyone can lead me to some information or help me out, please reply or reply and ask for my email address if you wish to talk about it personally. Also, what are the laws regarding marrying the older girl, since she is in her fathers custody fromw hat i know, would he have to approve and/or give up custody of her? Thank you all.