It sounds like he’s so overwhelmed and so fearful of failing that it has paralyzed him. I think an ADHD coach could be just what he needs — someone neutral to help him make a plan of action that takes into account his weaknesses and strengths.
While I don’t think abruptly throwing grown kids out is effective, I do think you have to clearly set boundaries and expectations for him to stay. You don’t want to enable the current status quo. I would sit down together and write up a contract that includes your expectations from him (1 job application a day and 2 hours of work on the house maybe), and what he can expect from you (a place to live, whatever else you pay for/provide him, and support and help when he asks for it). Writing it down makes it more real. Having a contract outlines what your expectations are, but also shows that you’re a team and willing to work with him. And having very detailed expectations gives him structure he needs in order to get his brain to initiate what he needs to get done.
ADDitude Community Moderator, Parenting ADHD Trainer & Author, Mom to teen w/ ADHD, LDs, and autism