other mangas should take note that you dont have to end a series when the main couple finally gets together. these extra chps with them together made the ending of this series better than 95% of the other ones.
this series needed this arc for some drama. the author already showed you it ends fine so i have no idea why people are complaining.
my guess is nasa promised to take her back to the moon or something after she explained who she was.
"here, take this kid you just met that has extreme bonding issues and finally became adjusted to me. just take him im sure it will be fine"
the fuck is wrong with you
so shes going to confess that shes his grandma, hes not going to believe it, and then the story will move on with her still looking out for him / talking to him.