Martin Short is speaking out for the first time about his daughter Katherine Hartley Short's death. "It's been a nightmare for the family," Short told CBS Sunday Morning of Katherine's death on Sunday, May 10, per Variety. "But the understanding [is] that mental health and cancer, like my wife's, are both diseases, and sometimes with diseases they are terminal. And my daughter fought for a long time with extreme mental health, borderline personality disorder, other things, and did the best she couldn't until she couldn't.