Vans or trucks or buses (not govn. ones in this case), or cars, are allowed to bring voters to the polls.
The voter is in control of what they want to do in the way of someone helping them through the process if they need that. One thousand or any number of voters may use the same person to help them - it is their call.
The person the voter selects to help him/her, may go into the poll to help the voter. The election judge will make the helper take an oath and sign a document. Then, the voter may take the helper into the booth with him/her. It is none of the judge's business what happens in that booth as the voter is god of his/her ballot and the helper he/she chose.
It works a different way if the voter asks for help from the judge or election worker. At the beginning of the day, the judge and workers take the oath about helping a voter and that oath applies for the rest of the day.
If a voter asks for help, TWO workers (from different parties if available), go into the booth with the voter. One helps and the other one makes sure the worker helper doesn't go beyond what a worker helper is allowed to do. The worker helper may interpret if language is the problem, or may read the English if the person cannot read. The worker helper, in the case of an electronic machine may show the voter how to get to the ballot. The worker helper may NOT suggest which candidate to vote for.
Of course, elections, even for federal offices, are administered by states, and no two states have exactly the same election laws. So the Texas law you cited may or many not be applicable to North Carolina, where the events which are the subject of this thread occurred.
I would have to say that Texas now probably has one of the more fair and honest election laws in the country, and you don't generally hear too many complaints about it.
But no matter how fair and decent the law is on paper, any state requires courageous, fair and decent people supervising the election in order to minimize fraud and cheating. Texas probably had similar laws when Lyndon Johnson was able to abuse the system back in 1948 when he cheated his way to the US Senate, which became his eventual springboard to the presidency.