Kao ni Denai Kashiwada-san to Kao ni Deru Oota-kun + - Vol. 1 Ch. 6 - Kashiwada-san's Grandma

[MangaDex]

 

[Weebmaster41]

I see where her older brother gets it from

 

[powersen41]

Ts some time travel thing i swear.

 

[Hacete]

I thought their grandma was still alive. Cause we see them in the main story. Which chronologically happens after these episodes.

I guess they are from her mother's side.