pellaz saidbet TX could find a Grand Jury to get the cop off.
reading the article, learn new things every day:
An inspection sticker is not required for vehicles with temporary tags.
Nor is it an arresting offense, merely earns a written citation. So the cop was wrong on 2 points of law: the requirement for current inspection with a dealer plate, and the correct response to a missing or expired vehicle inspection sticker.
Of course this cop will naturally claim the old guy was "resisting" and "threatening" him, making physical force justified. And the video may not be sufficiently clear on that point, they often aren't.
So while his own police force may suspend or even fire him, I doubt any legal charges will ever be filed against him. The old guy's best bet might be a civil suit against the city.