Gary Mendell was running a successful hotel investment firm when he lost his son to addiction about six years ago. After that, the direction of his life changed.

In the late 1980s, Mendell started HEI Hotels & Resorts which owns and operates properties under some of the biggest brands, including Starwood, Marriott, and Hilton.

"I was a CEO running businesses, and my older son, Brian, struggled with addiction for eight years," Mendell told CNBC's "Squawk Box" in an interview this week.

Brian tried marijuana in his teenage years, which led to his use of harder drugs and eight different treatment programs and therapies to try to stop, Mendell recalled.

"Each one was different," he said, claiming that none of them followed "evidence-based protocols, backed by research."

Ultimately, weighed down by the emotional weight of his addiction, Mendell's son killed himself.

"My son didn't die of an overdose," Mendell said. "My son hadn't used a substance in 13 months and he took his life. And he wrote about it in a note about the shame and stigma he felt about being a 'bad kid.' And that's just not my son."