Key stuck in ignition, seems totally dead

Lately when someone sits in the passenger seat, the overhead interior lights blink and the seat adjustment will not work. Today it would not start, like dead battery. Put new one in and now it won't do anything, key is stuck in ignition and won't go out of park, no lights, etc. Any ideas?

Check the wiring going to the seat and the seat belt buckle.

But would that explain the key being stuck? the steering wheel is not locked.