Future mother-in-law complains I am not "building a relationship" with her. Why should care?

FMIL is constantly whining that I'm not "building a relationship" with her. Newsflash: I have a very busy life of my own that FMIL does not fit into. I am helping my mother care for her disabled mother, my gran, I am enrolled in an intensive MFA program, have 3 jobs and working on opening a business with FH. I don't have the time or inclination to "build" a relationship with FMIL. She has too much time on her hands if she is worried about this. I have my own life and I really don't have time for this woman's pity party. Honestly, why can't she get her own life and leave me alone?