I was covered by Medicaid when I was pregnant with my first. You (or she) can visit www.yourtexasbenefits.com to print out an application (if she's never applied for state benefits, she can even apply online there).
She'll need to have written proof of a pregnancy as well as a bunch of other things (proof of income, bills, etc). At her interview with her case worker she'll be given a list of these things to fax, mail, or bring into the office before they can finish her case. I would take them to the office and get a receipt for them, as papers have a tendency to get lost! The process is time consuming, but worth it! Medicaid will cover everything for the pregnancy/medicaid accepting doctor/hospital as well as any unpaid medical bills she's had during the past few months (I think it's 3?); moreover, the baby will be covered for a year.
I lived with my parents when I had Medicaid. I did have to list their incomes, but they only counted what bills my parents paid for me or any amount of money they gave me regularly. I would think the same would be true of your daughter and her boyfriend. She needs to list the bills SHE pays (for instance, if their rent is $800, she should put that she pays $400) and the money SHE gets. Her boyfriend's earnings will need to be listed since he lives with her, but I don't think they'll count that as her money.
Good luck!! It'll be such a huge relief when she gets approved; I know for me it was! I had a c-section and the bills amounted to 20k. Yikes!