I really like E-musu Aki art and some of his stories are really nice, but this is not one of them for me.
First that she is cheating on her boyfriend for no reason (one that is not show in the story) and second she wanted to ruin something the guy treasured.
But is not like this younger brother is a nice person as well. in the end he pretty much says he hopes her to be with his older brother so they can keep fucking.
If i feel anything in this work is bad for the older brother.
When i saw the "spending the night with two ladies" i thought this looks like a threesome, but i saw vanilla and i was confused, but it was a good vanilla in the end.