It only takes a few min to wire in replacements.

Easy fix. Shut the circuit breaker off at the panel that controls the light switch. Remove plate....remove switch to box mounting screws. pull out ( should be plenty of wire to remove from box. Remove the wire from switch screws (2-3 )....go to hardware store and get equivalent switch....reverse the procedure described above.

I shut down the entire house in case of a potential ‘own goal’ by gramps.

It unlikely that you will run into aluminum wiring, since it was used only briefly in the 1970s. Over 99% of the wiring found in residences and apartments is made of copper.

Simple test to see that the power is off:

Switch the light/lights on.

Find the breaker that turns them off. ALL OF THEM that are controlled by the switches in that box.

Put a piece of tape over the turned-off breaker. In case of clowns on the loose.

Extra Credit: a neon tester is fine, cheap for testing inside the switch box -- and see link below.

Of course, work by day or with a battery lantern, CUZ THE LIGHTS ARE OUT.

Go replace it per OAITW r.2.0 #2 above

While you are at it, replace all in the same box. They must be the same age and dangerous by now.

Or ask someone who has done it.

https://www.wikihow.com/Replace-a-Light-Switch

Some switches have screw terminals "loop the wire". Some have "push the wire in and screw it tight"

2: spring for commercial grade (especially frequently plugged/unplugged outlets) whenever you replace electrical components. Buy once, cry once.