Accidently Saving A Human Kid

Error ends up saving a kid from an abusive home by accident and is then, through a one sided conversation, is decided to be their mother. And so he then proceeds to stop destroying and disappears from everyone.
Now Ink is getting concerned, fresh and geno are demanding that they find their brother, and blue is... why is blueberry smiling? Isn't error his friend?
Why is stretch not worried that error could be plotting?
And let's not forget to mention the freaked out classic because his crush disappeared.
(Do not own undertale or most characters used)