The officer stopped the car but there was not a traffic violation and there was no illegal conduct to justify the stop. The officer thought she needed his help because of "alcohol poisoning". Really? Ultimately, she didn't need his help at all. But once he stopped the vehicle, he "simultaneously" conducted a DWI investigation on the driver and arrested him.
The Fort Worth Appeals Court correctly decided that the officer, uh, you can't stop a vehicle for that.
But here is the official position of the Texas District and County Attorney's Association: