United Kingdom, Dec. 20 -- Nick Reiner's "issues were far, far out of his parents' control".

The 32-year-old writer has been charged with first-degree murder in the deaths of his parents - filmmaker Rob Reiner and producer Michele Reiner - earlier this month and insiders say the pair tried for years to help Nick deal with his addiction and mental health issues.

A source told PEOPLE: "They tried so hard already for years.

"At the end of the day, Nick didn't take the help seriously. This was true for years and years. His issues were far, far out of his parents' control.

Nick lied a lot. He was unreliable, but he was also convincing and intelligent. His family was empathetic to [his struggles]. They never lost hope in him, even when he w...