I'm sorry to hear about this. It's a perfect and unfortunate example of why we teach that riding on sidewalks and against traffic is dangerous.
If it happened as you describe, then to me the driver is at fault. He have been more careful when pulling out of a driveway, across a sidewalk, where pedestrians or kids on bikes may be present. I don't know what TX law says about this situation though, if anything. Unfortunately, the driver may not be charged if it's not clear that a law was broken.