What your friend’s MIL is doing will be done only by an educated person. She is teaching her DIL appreciation of labor and making sure that her DIL knows all of these very essential life skills . In case the table of time turns and they end up being poor and the DIL who would be enjoying her life in the lap of luxury will become bitter in bad times. I am sure when this MIL knows that her DIL has mastered all the necessary skills , the MIL will let her DIL enjoy life.
Just kidding , I do not know why a professor will make life of her DIL miserable and would not let her DIL live her life and enjoy it.