sure! she would technically be a half-sister or even a step-sister, a product of his dad and his step-mom or a kid she had before they got married, but mickey treats her like a regular sister. as in, he's obnoxiously protective, extremely bothersome, and texts her a hundred times a day with a running tally of his dumbest thoughts. i'm flexible on the exact family details/dynamic but i can make a custom if you'd like to discuss more!