I'm so sorry this happened to George, and hope he recovers. "If only it had been Casey, and fatal" was my first thought..
I think he would not choose suicide by vehicular means. Also, I believe he has been more " in the world" than he was when he made a suicide attempt in Daytona Beach years ago.
The 10 year anniversary of Caylee's remains being found may play into it but maybe by causing him stress which has exacerbated a physical illness or condition that was the underlying cause of the accident.
As far as the vehicle, Toyota trucks going back to 2003 were part of the Takata air bag recall. The recall does not go back further than 2003, possibly because the requirements of the law may have a cut-off date as far as age of the vehicle ( we don't see recalls about Pinto gas tank explosions 40 years later, for example) , and possibly because Takata didn't supply the air bags earlier on. IDK which, maybe both play a part. If a vehicle with an airbag is in a crash where the airbag deploys, it goes without saying that the airbag has to be replaced by a manufacturer's repair shop and then tested with computers which test the pressure inside the mechanism, for lack of leaks, and other technical things.
We own 2 BMWs of different year make and models and both have had to have air bags replaced. Our dealer checks all the air bags when the cars are serviced and there's been a loss of " integrity" or dependability factor due to the Takata air bag recall for one, and another had an original installation pressure problem that was detected by machinery BMW uses to test unused air bags in their cars.
Thus, it's possible George's driver's side air bag lost pressure on its own, as some do this and the truck is not only old, it's in the WORST state in the USA for humidity causing damage to delicate sensors, according to what I can find on how air bags work, and what makes them not work at times.
I have never owned a vehicle for over 8 or so years, but if I did, I'd worry most about the air bag system retaining its integrity as someone who also lives in a Gulf Coast ( humid) state.
I hope he is feeling sensation in his extremities now ( if the news report was accurate about lack of it at the accident scene) and has a very good prognosis.
It's not for me to say whether he and Cindy are right for each other or wrong for each other. That's their decisions to make for themselves. I do hope she will be supportive of him and help him to the degree he needs and she's able to provide or get the nursing staff help he needs if there's a long term problem.
My first thought was " brain tumor" because of his age, and because the first sign of a Glioblastoma Multiforme brain tumor is usually seizures. GBM tumors are the most common brain cancers in adults, and because of the way they invade brain cells, have a very high fatality rate.
I lost 2 friends to this cancer when they were in their 40's.. The risk increases greatly with age.
Both were unaware they were ill until they had their first seizures and imaging showed the brain tumors.
In any event, I don't think he's a bad man, I think he's been through a living hell that probably never ends. I hope he recovers fully, and is not vilified in this time of injury. I will be praying for him.