Loveless, Dengeki Daisy Recommendations
Both characters are in similar situations. They both lost their older brother, and have been entrusted to their older brother's best friend. The older brother's death is very mysterious and almost suspicious in both manga, and in both cases appear to be more important to the plot than we think at first.
Both main characters fall in love with their brother's best friend, who, in both manga, is an adult and much older than the Main, and is often referred to as a pedophile (jokingly by friends, usually.)
Both main characters are cute, awkward and shy, but still very mentally and emotionally strong and intelligent, unlike
Allthough Loveless is a shounen-ai and Dengeki diasy is just a shoujo I find the relationships between the two main characters and the situation with there dead, elder brothers similiar. Not to mention a sizeable age gap.
There is a shadow of misterious big brother over the main persons in both series. Age gap between couples. Computer and virtual world related things - I loved it in both series. And the cellphone - a bond between couple, an important thing in both stories.