Yeah, it's looks really clearly like that :D

I say he's the eldest brother! =P

there is a possibility that he is the middle brother. yeah as you can see he revealed to be akai in the scarlet return thing BUT before that maybe that was the middle brother all along since the first appearance of okiya and it was not akai on that mall case,or the case where bourbon reveals himself it was the middle brother for me.

Huh,Subaru is Shuichi in disguise