ULPT Request: What genuine illness/injury can I get/fake to skip graduation?

I will be graduating in 2 months, my parents are insistent on coming to my graduation and have booked flights to come to my graduation. The thing is I have lied about my major being in medicine while i’m actually taking liberal arts, they partially contributed to my college fees. My dad is emotionally abusive and can get violent, so I obviously cannot tell him. Can anyone help me out on how I can skip out graduation? Any advice, please but cutting contact with my parents, I have a younger brother and if I cut contact with my parents, I won’t be able to remain in contact with him. Thank you.