88 Camry key lock on steering column loose can't turn off

We have an 88 Camry with a button on the steering column. You must depress the button at the same time as you twist and pull out the key. Over time the button and key function has become weak. You can yank the key out without pushing on the button. But when you do this the car does not turn off completely. The next time you try to start the car the battery is dead. Is it hard to replace parts on the steering column? Can you get used parts from a junk yard? The key is tied in to the VIN number so I’m not sure this is a good idea…