It you are bed ridden and confined to bed it is very difficult to get up, travel to the PEA office and explain the situation.
I tend to think that her family would normally pay the bill, perhaps at a 7/11 if that were nearer.
Again I think that her family could have gone to the PEA with a letter from her doctor explaining the mothers situation.
Here in rural Kamphaeng Phet, my meter is read on 23/24 monthly and the payment date is the 3rd of the following month. If I forget, a reminder is put in the electricity box on the 10th of the following month.
How many bills you can stop paying before before being cut off I have no idea. 2 or 3 perhaps, depending on the size of the bill.