My friend is battling addiction and I don't know how to help

For some context, we're both teens and live in the same town, but I'm homeschooled and he goes to the local highschool. We communicate mostly through text messages and this morning he said that he's having a tough time with his weed addiction, he has asthma. He's just lost his grandfather not too long ago, so he's been smoking much more often lately. I can relate to losing someone close, but not to battling addiction. His parents are not helping him, even though they know he smokes. I tried telling him he's not alone, but I feel like saying that's not enough. Is there any way I can further support him?