Legal Question in Criminal Law in Texas

They cannot make you testify in the sense that they cannot pull the words that they want from your lips. However, they can subpoena you and if you do not show, they can have you picked up and brought to court and possibly put into jail to be released only with a witness bond. They can call you to the stand and ask questions and if you refuse to answer the judge can order you to answer or you can be held in contempt. If you provide answers different from the information that you previously provided they will impeach you by pointing out your previous statements.

I assume that you told the prosecutor you did not want him prosecuted? If not, tell the prosecutor. If they will not dismiss the case they may at least make him an offer that he cannot refuse.

You can cooperate with his lawyer, if you choose to do so, so that the lawyer is at least fully prepared at trial for your testimony.