When parents take in a kid, something beautiful happens. When they do it along with making their existing child invisible, something else happens entirely, and that something else is exactly what this story is about

These parents did an obviously beautiful thing. The only problem in the story their 21-year-old shared is they overshadowed it with a beautiful talent for rewriting history in real time. The kid they already had becomes background furniture the moment a more pressing project walks through the door, and somehow they are always shocked when the furniture eventually walks out too.