If he wants credit while he is in the custody of another jurisdiction (such as TDC), he should write to the jurisdiction where he has warrants asking for them to give him credit. They do not have to do so. Otherwise, if the tickets are not paid, he will still have warrants (although they will not put a detainer / hold on him in TDC for traffic warrants.)
You right attorneys can be great. It's my opinion that you are abusing the goodwill of the lawyer participants on this site. Think how great it would be if you had an attorney who you had hired whose advice you could rely upon.