Family Night

Hello! My fiancee and I have been listening to your content for quite awhile and we finally sat down and decided to commit to learning this system the best we possibly can! We are in year two of blending our family, I have 2 bio daughters 9 and 11, and my fiancee has her bio son age 8. We have them all full time and as we send more questions, I'm sure you'll learn plenty about us and the kiddos as well as all our quirks and dynamics. I'll try to keep the background information as short as possible.

We do a family night every week which has been tweeked and changed over time, the current version is that we all sit down together and watch a movie with popcorn. We rotate who gets to pick the movie each week and its been a nice addition for the most part. Our boy is very neurodivergent, and is very affected by his ADHD, making it very hard (impossible really) for him to sit through a whole movie. We have been letting him get up and play around the house independently when he loses focus. To my partner and I, we didn't see much of an issue, however in the last family meeting our older girl said that when he leaves it doesn't feel like we're spending time together "as a family" because "our whole family isn't there". We're wondering if you have any ideas of how to promote /keep him engaged in what we're doing as a family? And maybe another question would be how to promote doing a family night, or a certain activity of a family night, if one member of the family doesn't have interest for whatever reason? Whether that's because movies are boring, or they'd rather spend time alone or with friends, if they get overstimulated and need to leave for a time, or if they just want to do their own thing?