2011 Dodge Grand Caravan brakes problems

Tl* the contact owns a 2011 dodge grand caravan. While the contact's wife was driving approximately 30 MPH, the vehicle did not respond appropriately when the brake pedal was depressed. The contact depressed the brake pedal all the way to the floorboard, but the vehicle still failed to respond. As a result, the driver rear ended another vehicle. There were no warning indicators illuminated prior to the failure. The air bags deployed.

The vehicle of record has been spontaneously shutting off all day, it shut off 15 times in 1 parking lot, but the most dangerous aspect was when it shut off while I was doing the speed limit in a 50 and a 55 MPH zone. It will generally shut off randomly, but primarily at stop signs or backing out of parking spaces, but there have been 3 instances where it shut off at 40 MPH or higher in the last 8 hours, when these shut offs happen it takes 5-10 attempts to restart the car.