Martin Short opens up about death of daughter Katherine.

During an appearance on CBS News Sunday Morning, the Only Murders in the Building star described her death as "a nightmare for the family". Katherine, who worked as a clinical social worker, died by suicide at age 42 in February. "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 could until she couldn't."