He needs to hire a lawyer to assist with this. He may be entitled to relief under Article 62.354 of the Code of Criminal Procedure.
See Chapter 62: http://www.statutes.legis.state.tx.us/docs/CR/htm/CR.62.htm
The information provided is not advice but a legal perspective and you should schedule a consultation with the lawyer of your choice.
This law is very complex, and you're talking about two different states and juvenile and adult law. This is not something that someone online will be able to answer adequately. You need to hire a criminal defense attorney who can sit down and research all of this thoroughly, and based on your specific circumstances. This isn't something that will likely be part of a free consultation, as it will probably take several hours of research. If judgments and records need to be ordered, it will take even longer. Call around and ask what attorneys might charge for this.