First of all, let me say how glad I am that you are a very supportive mother.
I've known of cases where the parents of their citizen son/daughter do not approve of their child's relationship solely on the fact that the other person is undocumented.

What she should be doing to qualify for the Dream Act, which is the only piece of legislation by which undocumented students like us can become legalized, is to stay away from any legal/civil problems and be a contributing member of society (pay taxes if possible, volunteer, be of "good, moral character"). Based on what you have written I am sure she would be a prime candidate for the Dream Act.

Marriage to your son would be the fastest way for her to become legalized, but as you say 19 is a bit too young. Although you may take into consideration their maturity level and how long they have been in a relationship to determine if marriage is a good option for them at this point.

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