Battery drains because the vehicle seems to think there is a key in the ignition

Some of the dash lights come on at random. The door dinger goes off at random with no key in ignition. When you put the key in ignition some dash lights come on without turning ignition on. My friend who owns it is a Toyota Tech and he has checked quite a few things. No codes. Pulled all connectors that could be associated with it and cleaned them. Pulled fuse box and totally took it apart and cleaned it and put it back in. I know he only has one key for the truck and the remote doesn't function. Not sure if that would have anything to do with it. Just throwing that into the mix. I'm asking without his knowledge because he may be too stubborn to ask. Lol