From Forever More:

After being told that his dad passed away, Souichirou came back to the house which was his home 8 years ago, and there he found out about the existence of his 2 older brothers, the eldest - Masato and the younger - Kaname. In order to receive rights to the house, Souichirou has to live together with them, and despite the chaos and arguments, it's fine by Souichirou if it means he can get the house. But one day, he accidentally sees Masato kissing Kaname...