Rob and Michele Reiner "thought they had more time" to help their son Nick.
The renowned Hollywood director, 78, and his producer wife, 70, were found dead inside their Brentwood, Los Angeles, home last week and their son Nick, 32, has been charged with two counts of first-degree murder.
However, friends of the Reiners have insisted the couple were trying to help Nick with his addiction and mental health struggles and the pair never gave up on him.
A source told People: "His issues were far, far out of his parents' control. He didn't take (his parents') help seriously. This was true for years and years.
"They never lost hope in him, even when he was scaring them or making their lives harder.
"Nick had so many good days too, (his struggles) would change day to day. They thought they had more time before it resulted in tragedy."
Another source said: "They did an admirable job balancing parenting and work. but their kids are all adults now and they had tried so hard already for years."
And friends believe the Reiners - who also had two other children Jake, 34, and Romy, 28 - would want empathy for Nick.
Douglas Shaffer, who produced Rob and Nick's 2015 movie Being Charlie, told People: "There's lots and lots of healing that needs to be done. I think they would probably want people to feel empathy towards Nick's struggles. And perhaps forgiveness down the road.
"Rob was a proud father, a loving father, along with Michele - she was a loving mother ... Nick had a good support system, as far as I knew."
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