Breaking a rental lease?

I live in AZ-I am 4 months into a 12 month apt rental lease. My mother is my co-tenant on the lease. She has terminal cancer and needs hospice care right now. So, I have to move. But my landlord says there is nothing in the law that allows me to break a rental lease. I cant believe this , that the law does not allow for a case like mine. She says if I break the lease, she will go after me in civil court, get a judgement, get my wages by garnishment, get my car that is only worth about $2000. She says I will never be able to get another apt in AZ if I don't pay her something outrageous like 3 months rent + admin fee+lease break fee. HELP!