can insurance company refuse to passenger for injuries sustained in a auto accident if both the driver and passenger had been drinking?

If you are hurt as a passenger when your driver is drunk and at-fault for the wreck, the insurer will try to claim that you knew that the driver was drunk and that you assumed the risk of injury by getting in the car with them. These are tricky cases and depend on the extent of the passenger's knowledge of the drinking and level of intoxication of the driver. They can be won and sometimes the insurer can be forced to accept some responsibility if you can show that you did not realize or were mislead about the driver's ability to function.