She could get a 2 bedroom and share 1 bedroom with her daughter, boy get a bedroom. Or she can sleep in basically the living room by putting up a screen or divider. My grandparents had a house but they rented the top floor, and there were 2 rooms that could be used as bedrooms. My mother got 1 bedroom, her brothers shared a room, and the parents slept in a pull down "murphy" bed in an alcove in the kitchen (the pantry was changed into a closet).
If you need to do it you can do it. My friend had 3 kids and lives in a 2 bedroom. The mom gets the smaller room and the kids all share a bedroom.
My Dad when he first moved to the US lived in a 1 or 2 bedroom apartment that held 2 families. Beds in a number of places, no privacy.
I feel for her though. It must be scary to start over and figure out how to both hold a fulltime job down while taking care of 2 kids. the working and childcare issue is bigger than the 2 or 3 bedroom apartment issue.