Pic:
http://i50.photobucket.com/albums/f320/tosay_guild/pp/misc/piano.jpg

The manga is 'bout a guy that is looking for his brother, so his brother can take over the family business. One night he meets a man and ends doing "it" with him. They start living together, but he finds out the man was actually his younger brother. Let's see after that it turns out the younger brother knew thay were related. He got kicked out. The younger brother started to live with his step brother I think. Then the older brother takes the younger brother back because he is in love with him and they start living together again. Something like that anyways. Oh and the younger brother plays the piano, if that helps.

The manga you are looking for is called Uso to Kiss by MINASE Masara.

I like this story so much, I went and order a copy from amazon 😀