Watch unaired footage of Michael and Marie from Marie's 2009 appearance on The Oprah Show.
"[He] was probably the easiest child of all my kids," Marie says. "He was so fun. And cute. And darling. It wasn't until my son started using drugs that I saw him change."
Marie says Michael first started to abuse drugs when he was just 12 years old. He was in and out of rehab before he got clean—and he wasn't the only one who benefited from the help he received in treatment. Marie says she learned so much about being a mother while Michael was in these programs.
"We can have all the knowledge in the world," she says. "But it's the wisdom that we need to find."
According to the toxicology report, Michael was not under the influence of any drugs when he jumped to his death from his eighth-floor apartment. "There were no drugs in his system," Marie says. "But I believe the ramifications of them were there, and that was the hard part."