Recreational Vehicle Lpg Tank Valve/gauge problems of the 2007 Cadillac CTS

I was driving down a major highway with my 2 small children with the ac on when all of a sudden all the gauges in the car dropped to zero and the car inside became very hot and the steering wheel tightened up. I immediately gripped the wheel as tight as I could and moved to the side of the highway. I thought we were going to crash. I had no control over the vehicle, it was shutting itself down while I was driving. When I pulled over I had to force it into park. This is an extreme safety issue, we could have been hit and killed by another car. It happened so fast. Another incident that occurred today was that I parked in my driveway and tried to turn my car off and the key would not move or come out of the ignition switch. The car ran for a while and than shut off, but the headlights lights were blinking very fast and did that until the battery died and the key is still stuck in the ignition and will not come out. This is not the first time this has happened. Usually the key will come out after multiple attempts, but I have had to replace 4 batteries from the time I purchased this vehicle in March of last year until now. I will never buy a Cadillac vehicle again.