If the dog came form a mill or not it should not be bred by someone who knows nothing about breeding let alone to pay their rent !! Have your roommate read some of the posts here on YT about things that have gone bad with whelping. I hope she has saved plenty of money incase the mom needs a emergency C-SEC. That cost alone can be $1,200. Who is she going to breed her to? Some random male? Most people would also charge a stud fee and require that the female be tested for STD's. Another cost to your roommate. If the mom get sick or the pup won't nurse, your roommate will have to bottle feed every 2 hrs.
How in the world could someone get a mom from a mill just to put her through another breeding? 
If she cared anything about this 3-4 lb mom , she would never even consider breeding her !!! IMO.