Have him update his resume within 2 weeks. If he's anxious about it, figure out when the next resume workshop is in your local public library.

Then about one application sent out a day till it pans out. He's not busy. He can do that, but he has to want to.

If you set him up to succeed and he still lazily fails, I'd start making plans to live by myself. (Even if that means selling the house.) I wouldn't divorce him just yet, but I think if he was forced to live with his parents or figure some shit out with the knowledge you won't financially support him, he'd figure it out.

Once the plans are set, I'd make one last effort to convince him to get his shit together. No more weed, all the weed currently in the house goes down the toilet. No booze if he's been drinking too. Serious daily strides where possible OR he goes to a therapist and stays at a therapist for 6 months or more. If he wants to pursue a dream, he does it while he has a job like a responsible adult. If no daylight, pack your shit and live separate.