It definitely takes time to find your footing as a young adult, especially when you have ADHD (and it’s a new diagnosis). Plus, those with ADHD are several years behind developmentally in many areas, especially executive functioning (which helps us control our lives and succeed).
I would create a contract between parent and young adult. Parents will pay rent as long as child is taking meds and seeing therapists regularly, and making a full effort to become and stay employed. Maybe limit this to 9-12 months to give him time to figure out how to manage his ADHD and succeed on his own. Then maybe you step it down so that he becomes more and more responsible financially. Maybe months 9-12 he’s responsible for 30% of his rent, then months 13-16 he’s responsible for 60% of his rent, then up to 100%. In your contract, make it clear that you are always there for him when he needs help and support.
ADDitude Community Moderator, Parenting ADHD Trainer & Author, Mom to teen w/ ADHD, LDs, and autism