When I was diagnosed with adult ADHD, only a few people in my family managed to convey a sentiment of understanding. The rest were a little bit more abashed or confused. However, they didn't judge me or anything, and I realized I don't need them to understand it. I quietly do my thing in my private life, and it doesn't really affect any relationships with family.
I had to answer some questions a couple times, but I know they were just curious and trying to bridge that gap of understanding, because they cared about being able to relate to me. In the end, I don't think they really understood, but I know their inquiring came from well-meaning intentions, and gradually things moved on after that.
So in the event you have a similar situation, just wanted to communicate that it can be quite alright if family members don't understand it. Not saying that you have to be okay with it, but just sharing how it turned out for me. However, the caveat is I've reached a point where...