Kodomo No Niwa

From Pink Rose Scans
Saho, in her opinion's, lived a pretty happy life up until now with her mangaka father and a grandmother she lovingly calls "Granny." Sure, they don't have the luxuries of more wealthy families, and she hates how her father has NO care for his fashion sense when he lounges around in sweats all day, but when it comes right down to it, she couldn't love her home more.
However, their peaceful life's disrupted one day when they receive a phone call saying that Saho's mother, who had left her father years ago taking Saho's older brother with her, had passed away. This leads to Mugi, a brother she hadn't seen in ten years, coming to live with them.
She has a hard time adjusting to life with the brother she'd only known from faded family photographs--and his selfish and egocentric nature's not helping matters! Will they ever learn to get along?