My Brother's Fiancee Is A Prostitute I Slept With, Should I Tell Him?

In 2012, I was transferred to Ibadan. I have
lots of girlfriends in Lagos and don’t want
to date any new girl in Ibadan, so me and my
friend that was transferred together became
regulars at a brothel.
Me and my friend had just 2 customers we patronize. 6 months later (early 2013) I was
transferred back to Lagos. After I left, I do
invite one of the girls to Lagos because she is too good in bed till I lost her contact when my phone got lost (December 2013). We all traveled home recently for the Sallah
celebration. I was surprised when I saw my
younger brother come with the prostitute in
Ibadan and introduced her to me as his
fiancee…

I just stood there not knowing what to do because I was expecting the girl to feel
somehow but she didn’t even show any
fear. Throughout the day she was
everywhere cooking and joking with
everybody around there.
I thought she was pretending not to know me but I didn’t confront her, so I asked for
some of her pix from my brother and sent it
to that my friend if he knows the girl and he
was quick to tell me that’s the girl I do
“rough handle” on bed in Ibadan.
But when I told him of the relationship between my brother and the girl, he told me
to tell our parents and my brother so they
can cancel the relationship that the girl isn’t worth it.

Now am confused, I don’t know if the girl is pretending or she doesn’t recognize me
anymore because of her numerous
customers. I don’t know if I should tell my
brother or just keep quiet.