Martin Short ‘Shutting Himself Away’ After Daughter Katherine’s ‘Unfathomable’ Death at Age 42 (Exclusive)

Martin Short is struggling to cope with the sudden loss of daughter Katherine, an insider tells the National Enquirer.

Emergency responders discovered the social worker dead from a self-inflicted gunshot wound at her Hollywood Hills home on Monday, February 23, TMZ reported. She was 42.

“Martin is finding it almost impossible to process,” reveals the insider. “He’s been shutting himself away, trying to handle the practical arrangements while being there for his sons.”

The Only Murders in the Building star, 75, and late wife Nancy Dolman — who passed away in 2010 after fighting ovarian cancer — adopted three children together: Katherine, Oliver, 39, and Henry, 36.

“Martin adored Katherine — the sun rose and set with her,” the insider notes. “He knew she was going through a hard time mentally, but not to this extent. It’s just shocking and unfathomable to him on every level.”

On her now-deleted professional website, Katherine wrote about requiring a service dog amid a five-year battle with mental illness, per Page Six.

“Her suicide has taken a wrecking ball to Martin’s world,” says Enquirer’s insider. “But he’s an extremely private guy, so it’s been hard for loved ones to be there for him. Martin seemingly isn’t open to accepting help.”

Steven Spielberg, Eugene Levy and Kurt Russell are among the famous pals who’ve been seen attempting to comfort the mourning comedian, according to the Daily Mail.

Rumored costar-turned-girlfriend Meryl Streep is also “concerned” for Short, the insider tells Enquirer.

“Even she’s having a hard time getting through to Martin right now,” shares the insider. “She loves Martin unconditionally and it’s just devastating to see him so shattered and broken.”