Interior dome light does not turn on

Hello, I hope that your Thanksgiving was full of food, fun, and family!
My father recently purchased this car, from an elderly lady. My father has been fooling around with this car for about a month or so (checking fuses, bulbs, and etc), installed a new a new switch in the dash, the lights under the doors come on when you open the doors, but still can not figure out what is causing the rear interior dome light to not come on, as well as the light in the trunk. We do not know how long these lights have been out.
Also, the gas hand does not work in the dash, it started trembling and then stopped working all together. Do you happen to know what would cause these issues and what the fix is?
My father kept tinkering around and took a hot wire from the fuse box and touched the dome light switch in the dash board, caused a spark and now the car will not start at all. Do you happen to know the best thing to do? I have tried to talk him into talking it to the dealership.

We would greatly appreciate your assistance with this, it has been a very troubling thing for quite some time.