Depends what happened prior to the video starting and there's still a lot we don't know what was going on. Safer bet would be to follow within reason and guide the police in
Probably not considered brandishing since he's stopping a felony and he could articulate a lot of car thieves posses weapons.
People have a right to use reasonable force to protect property. The stop was fine and he could yank her out of the car, as unarmed or gun concealed. People try to prevent theft all the time. If she whips out a gun or knife outside the car as a threat, then he can draw and defend himself against death or serious bodily injury, depending on the circumstance.
Per the law if he can retreat safely he must do so. Like if she's still in the truck and whips out a knife while he's a good distance away.
"People have a right to use reasonable force to protect property"
On their property or business or property they
were legally responsible for, on their property or business.
Anything else and you are risking lawsuits.
I'm not a lawyer but I once chased down a shoplifter while I was "on the clock", and restrained him
on a public sidewalk till the police showed up.
I recovered my Bosses property, a six pack of Budweiser 16 oz cans.
Cop told me the only reason I wasn't arrested for assault and various other things they could dream up is
he was a strong, healthy, young, adult male, and I was a minor.
This was in a Hispanic community and I'm a white kid.
Waste of time to deal with it.
