Rear dome light will not turn off

[Pappa G]

Issue: The back seat dome light will not turn off and battery is now dying.
Question: Is there a stupid easy fix for this?
Is there a button that turns if off?

Sad story: Hi folks. I'm in a pickle and need some emergent help with respect to a 1984 300d that I gave my father. My father is handy, but the problem is that he is in the hospital for a stroke; I live 8 hours away; and my 68 year old mother is driving this car for the first time..... and has no idea how to operate a 300d. She was driving to the hospital to see him and wanted to turn on the AC (that does not work of course) and hit every button on the console...

Now the back seat dome light won't turn off and the battery is dead.

Is there an easy fix here? I researched and learned about door switches etc. I want to know if there is a stupid fix. a button? I cannot visualize the buttons on the dash.

Any help that will enable my 68 year old mother, 8 hours away, with no mechanical experience to turn off the dome light?

Thanks much in advance.