Here's a suggestion: Non-criminal defense lawyers and non-Texas lawyers should not attempt to answer Texas criminal defense questions.
I generally believe that it's better for an accused to be out pending trial. It makes the defense much easier for me, and allows him to show how well he can do.
But Ms. Treviño's advice is terrible; possibly the worst advice I've ever seen in response to an Avvo question. You haven't given nearly enough information for someone to advise you on changing lawyers.
If your son trusts his court-appointed lawyer, he should stick with him and follow his advice no matter how much it hurts. If your son does not trust his court-appointed lawyer, he needs to either find trust for him or change lawyers.
If your son trusts his lawyer, then you have to ask whether the judge will let him keep the court-appointed lawyer if your son bails out. If not, that might be a consideration that would lead you not to bail him out. Better that he be in jail with a lawyer that he trusts, than out with a lawyer he doesn't trust.
If your son doesn't trust his lawyer and can't find a way to trust him, your first priority -- before bailing him out -- should be to get him a lawyer that he can trust, even if that means he stays in jail while the case is pending; your feeling about that is correct.
If your son has not been convicted of a felony, that'll get sorted out eventually. Six weeks in is probably too early to expect the State to understand that the felon-in-possession charge was erroneous.
When a person is on bond, he's under the rules of the court and the bonding company. Either of them could conceivably order him to stay in Dallas County, but people often are on bond in one county while living in another.