There are procedures that you can do, in order to protect yourself. My personal opinion is that if the lawyer was not able to practice, at the time that you paid the retainer, the lawyer should not be entitled to it.
If your lawyer was already disbarred when he was employed by you, then you need to contact the police department in the city in which he "practices" and file criminal charges against him for falsely holding himself out as an attorney, which is a third degree felony in Texas (Penal Code 38.122). If he WAS a lawyer when you employed him, but later lost his license, it's more tricky. If the "lawyer" truly did nothing for the fee, he should have to pay it back. If he did any work, he might be entitled to keep all of it, or at least some of it. You should find out why he was disbarred - he may have taken fees from others and not done any work. Unfortunately, since he is disbarred, you have lost your best ally in a battle like this, which would be the State Bar. You should still contact the Bar and see if there is any help for you or whether you can make a claim under the Client Security Fund.
Disclaimer: This answer does not constitute legal advice, but is for discussion purposes only. This response does not create an attorney-client relationship between the person posting the question and Sharon E. Conway, Attorney at Law.