Robert Downey Jr. — who famously battled substance abuse in the past — accompanied his eldest child, Indio Downey, to the well-known rehab facility Cliffside Malibu in Malibu, Calif., following the 20-year-old's arrest for cocaine possession on June 29.

But the teen has allegedly been battling addiction for years. A family friend told the MailOnline, "Indio's been using drugs and hard drugs as well for eight years so there's been a million interventions and conversations and threats and AA meetings and sponsors. The list goes on."

The 49-year-old actor convinced Indio to check into the treatment facility, as the Iron Man actor hopes its innovative approach will help get his life back on track.

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The friend added, "Bob not only knows about Indio's struggles, he's tried everything, as all parents do, including kicking Indio out of the family home, followed by boundaries and tough love. None have worked."

The insider continued, "Cliffside may work because it's got an approach that Indio will hopefully not resist."

He's not happy about being forced into rehab, but the friend revealed, "His dad's lawyers are insisting in hopes of a plea bargain when court time comes. This means that since Indio is not choosing to get clean on his own but is somewhat forced to, the sobriety may not stick."

Robert, who also has a two-year-old son, Exton, with wife Susan, released a statement on Monday claiming his son "likely inherited" his weakness for substances, but added, "There is a lot of family support and understanding, and we're all determined to rally behind him and help him become the man he's capable of being."