It is common for folks with ADHD to hyperfocus on new relationships and then find that the intense interest falls away.
You broke ties with him for a reason. Is that reason still valid for you? I think that’s the question you have to ask.
And, don’t take ADHD behavior personally. If the change really is due to his ADHD, then it doesn’t necessarily mean he stopped caring as much.
ADDitude Community Moderator, Parenting ADHD Coach & Author, Mom to teen w/ ADHD, LDs, and autism