Without knowing details of number of people booked versus number actually staying, in addition to either a huge additional charge or being kicked out of the hotel, the following situations could arise:

OP and sick auntie being forced to share a single twin bed in a room not much larger than the bed.

Four people sharing one double bed, in a room booked for two guests.

Four people sharing two narrow twin beds, in a room booked for two guests.

Etc.

None of this is good.