You are asking a lot of questions...
Emancipation - called REMOVAL OF DISABILITIES in Texas - she probably does not qualified -- unless she supports herself totally. She will need money for an attorney. Anticipate $5,000 for an attorney. Judges do not like these lawsuits. You are in Houston (Harris County). There are lots of lawyers on this website.
Legal action a 16 year old can do - nothing - she is a minor. She cannot go to court without an adult representing her. As a minor child she has no rights in the State of Texas.
If she is miserable, she needs to talk to an adult - like a physician, clergy member, or counselor/therapist at school.
You and your parents have no rights to interfere in her homelife. Your parents cannot represent her in any legal action. I assume you are not her relatives. Your parents would probably be advised by an attorney not to get involved in this matter. I assume that they have no consulted with an attorney.
If her life is in danger, then a local policing agency and/or CPS should be contacted. However, once this is done, you cannot stop the ball from rolling...she will probably be removed from the home and placed in a facility far away...possibly in foster care or in a large facility outside of Houston -- away from you with no access to you. So be careful what your next step is -- you might both regret opening this door!
Foster care is often worst than living where she is now! She will NOT be placed in your home - you are not related and CPS won't place in your home because the odds are that the two of you will have sex.
If her parents don't like your interfering, they can stop her from having any form of contact with you so be warned and aware of this.
By the way, I receive emails like your on a weekly basis. It will get better for both of you.
Fran Brochstein has over 20 years legal experience & enjoys educating the public about Texas laws. She is a full-time family law mediator in the Houston area. If you found this answer "helpful" or "best answer", please select the button to show your appreciation. Please understand that this is not a personal consultation and in no way creates an attorney-client relationship. You are strongly encouraged to consult with an attorney in your county in person about your specific legal problem. You can contact her at 713-805-9591 - 7 days a week - her personal cell phone.