Get specific time-based concessions, the sooner the better. “Tomorrow, I need you to clean the kitchen because I’m taking Johnny to blah blah.” Then set up an autoscheduler to email a reminder.
Also, start pitching stuff he leaves around and won’t clean up into boxes in a closet or the garage. Tell him you’ll be doing it. When he wants something, either he cleans it all up or the next time things go in the trash. Weirdly, some people with ADHD particularly are okay with a massive effort when they really are in a bind but more greatly resent having to do little “unimportant” things.