
I read too many fiction and yaoi to the point i can guess there is two possible route. 1. the lil bro like sis in law or 2. He is in love with his brother

And what are you talking about? His brother in law?? Are talking about the same manga? It' s about of someone who like his own bro and he sad when he now that his bro guetting married with his future " sister in law" because he is jealous. And some other guy can hear his heart's song...so are we talking about the same manga in this topic?
Now i remember that i really like the combination of baby pink and silver/grey. No wonder i love seeing both Yeni and Erudian