Martin Short is speaking candidly about the devastating loss of his daughter, Katherine, revealing she battled serious mental health struggles for years before her death.

In an emotional interview with “CBS News Sunday Morning”, the comedy legend described the tragedy as “a nightmare for the family,” while reflecting on the painful reality of severe mental illness.

Short explained that he’s come to view mental health conditions the same way people understand physical diseases like cancer — something he knows personally after losing his wife, Nancy Dolman, to ovarian cancer in 2010.

He said the family came to understand that mental illness can be terminal in the same way other diseases can become fatal, adding that his daughter did everything she could before reaching a breaking point.

As we previously reported … Katherine Short died from a self-inflicted gunshot wound to the head … according to her L.A. County Dept. of Public Health death certificate. She was found behind a locked door in the home … and a note was found on the scene. The contents of the note are still unknown to the public.