Self-Solving Problem, I Think...
...If this fellow is buying a car from a buy-here-pay-here lot, he's going to need to show a valid driver's licence as proof of identity, as well as proof that he's licenced.
If he has no licence, that should pretty much give any reputable lot pause.
He'll also need a D/L to get insurance, which will be required on the car by the lot. Buy-here-pay-heres generally require full coverage on the cars they sell. Again, this guy won't be able to produce what's needed to comply.
Unless laws and the DMV's regs are sharply different in Texas, this guy's ineligibility will surface at some point in the purchasing process.