The elder actor, 74, admitted as much in an interview with Radio Times published Monday. Charlie Sheen was addicted to drugs and alcohol when his dismissal from CBS series Two and a Half Men sparked a series of public rants and erratic episodes.
"What he was going through at that time, we were powerless to do much," Martin Sheen recalled. "You try to be present as possible. But you have to be aware of the circumstances. You have to be aware of many things that the public is not aware of."
"Only those of us that knew him understood what was going on," he shared. "I'm talking about steroids, at that time. He was in a very desperate situation. And he was doing what he felt would get him out of it -- going public. And it was very painful. No less painful for him."
Charlie Sheen made headlines at the time for declaring himself a "warlock" with "tiger blood" and railing against Two and a Half Men creator Chuck Lorre and CBS. He also embarked on disastrous one-man show My Violent Torpedo of Truth/Defeat Is Not an Option.
Martin Sheen himself struggled with addiction, and has been sober now for nearly 30 years. The actor currently stars on Netflix series Grace and Frankie with Jane Fonda, Lily Tomlin and Sam Waterston, while Charlie Sheen last appeared on ABC sitcom The Goldbergs.