You can pump in between feedings to store some for future feedings. Also, you can freeze it for later...keeping it from spoiling before the following weekend.
I’m currently exclusively pumping for my daughter so I’m aware of this. Fortunately I’m an overproducer and have a freezer drawer full of frozen milk. However, since she is specifically nursing, how does she start the process? If she pumps between feedings it will take a while to increase her supply. There are no breast milk substitutes, and the father is being a douche for denying his daughter proper nutrition.