Komi Can't Communicate - Komi's Mom is as cute as ever

She's a self proclaimed eternal 17 year old. Plus, she looks like what a sister for Komi would look like, so she like to play along with that.

IIRC, I think part of why she refers to herself as eternally 17 is because she was 17 when she met her husband, and is just as in love with him now as when they first fell in love.