Martin Short has spoken publicly for the first time about the “nightmare” of losing his daughter Katherine earlier this year.

The “Only Murders in the Building” star told CBS in an exclusive interview aired Sunday that Katherine’s death by suicide back in February has been devastating. Katherine Short was 42 when she died, according to media reports at the time. She was one of three children the now 76-year-old comedian adopted with his wife, Nancy Dolman, who died of ovarian cancer in 2010.

Speaking ahead of the release of a new Netflix documentary about his life, Canadian-born Short said that “it’s been a nightmare for the family,” but he explained that it has helped him to understand that “mental health and cancer (like my wife) are both diseases, and sometimes with diseases they are terminal.”

He went on to tell interviewer Tracy Smith about his daughter’s long-term struggles. “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. So Nan’s (Nancy’s) last words to me were ‘Mart, let me go’ and she was just saying ‘Dad, let me go.’”