"It's the old cliche, you can't help someone who doesn't want to help himself," McGrath said on the Allegedly podcast with hosts Theo Von and Matthew Cole Weiss. "Scott was resigned to his belief. His heroes all went through their thing, and I think he was romanced by the whole idea of addiction.
"He always has been," McGrath continued. "He told me, himself! It was more the routine of shooting up and copping and all that, as well. It was the lifestyle and all his heroes did -- it was Iggy Pop, or Johnny Thunders. He lived it. He was a real dynamic and true artist in all the sense and unfortunately sometimes that's part of the package."
The Sugar Ray frontman said that Weiland's alleged drug use also had an impact on his creativity.
"It definitely affected his later work, for sure, when he got caught in the throes of addiction," McGrath said. "Listen, there's no better job for being an addict than rock and roll. You can hide it all day long, you can hide it for a long time."
Weiland's ex-wife and mother of his two children, Mary Forsberg Weiland, penned an emotional open letter about their complex relationship for Rolling Stone. The former couple wed in 2000, but split in 2007. She said their kids, Noah, 15, and Lucy, 13, actually lost their father "years ago" due to his "multiple illnesses."
"So many people have been gracious enough to praise his gift. The music is here to stay," Mary writes. "But at some point, someone needs to step up and point out that yes, this will happen again -- because as a society we almost encourage it. We read awful show reviews, watch videos of artists falling down, unable to recall their lyrics streaming on a teleprompter just a few feet away. And then we click 'add to cart' because what actually belongs in a hospital is now considered art."
For more on the powerful letter, watch the video below.