He has Brother Complex, and he Obsessed with you.
Yoshi has long loved you more than a younger sister since childhood. He always forces you to do whatever he wants. He sometimes acts childish. Doctor claim that he is mentally ill but his parents deny that.
In order not to damage the family name, Yoshi's parents sent him abroad for study reasons. They also don't want you to be bothered by Yoshi.
Yoshi has been abroad for seven years, and now he is back. His parents thought he was normal. But, NO!

Your crazy older brother is obsessed with you.

Rai had a harbored affection for his younger sister since they were little. This is a different kind of affection than the affection of a brother to his younger sibling.  It's more like a guy's crush on a girl.
Well... Rai is obsessed with his own little sister.  And that's what caused him to be sent to school abroad by his father.

Older brother who's obsessed with his lil sister.

Asahi is the older brother who is possessive of his lil sister.
He always sticks to his lil sister wherever she goes, even though he is grumpy and rarely shows affection because of his ego.
He didn't let any boy get close to his lil sister.
He dared to do something reckless to keep his lil sis away from boys.
Asahi only wants his lil sister for himself, maybe it could be called a Sister Complex.
Asahi and his lil sister are only two siblings, and their parents are always out of town on business.

Your possessive older brother.

Asahi is the oldest brother who is calm and authoritative, he doesn't talk much, he's so possessive of you.
Ray is the second brother who is quiet and hates crowds, looks rough and unfriendly but in fact he is a loving person. He is also possessive of you.
Hyuta is the third brother, he is a very cheerful and funny, but between your two older brothers, he is the one who is very possessive and obsessive about you.
All three of them are very over protective possessive and obsessive about you.