Immobilizer/throttle body/ignition issues

The car sat for 6 years, nobody touched it literally. Then my buddy went to put a new battery in it and start it the key that he had was the wrong one so he proceeded to break the steering wheel lock and remove the ignition switch. The tumbler is trashed. I went to go start it, and put a brand new battery in it, and it started right up but the dash lights did not work and I drove it home. On my way home I noticed that it would not do above 30 MPH at the top of first gear. It would not shift. So I ran some codes on it and I saw that I probably need to replace the transmission throttle body sensors. So I wanted to clear the codes so I connected both battery terminals together with no battery to drain excess power. I left the car like that overnight. When I went to go hook a battery up to it again I got no power. I reset the ECU by turning the plastic screw with a flathead screwdriver all the way off then all the way back on. Keep in mind I do not have a key for this vehicle whatsoever. The only thing that I replaced was the ignition switch. I read somewhere that there is an immobilizer immobilizer that is preventing the car from doing anything. How do I deactivate it with no key? And why aren't I getting power after I cycled the contacts together in order to reset the ECU? Did I leave the cables on too long? And do I need to get a new tumbler assembly? It does not have a transponder key or fob. I am starting it with a screwdriver.