Introducing a man to her husband,a woman said,"His brother's father is the only son of my grandfather." How is the woman related to this man?

$A$ family consists of six members $P, Q, R, X, Y$ and $Z$. $Q$ is the son of $R$ but $R$ is not the mother of $Q$. $P$ and $R$ are a married couple. $Y$ is the brother of $R$. $X$ is the daughter of $P$. $Z$ is the brother of $P$.
Which is a pair of brothers?

$A + B$ means $A$ is the daughter of $B$; $A - B$ means $A$ is the husband of $B$; $A \times B$ means $A$ is the brother of $B$.
If $P \times Q + R$,which of the following is true?

$A$ woman introduces a man as the son of the brother of her mother. How is the man related to the woman?

Pointing to a lady,Suresh said,'She is the daughter of the woman,who is the mother of the husband of my mother'. What is the relation of the lady to Suresh?

$A + B$ means $A$ is the son of $B$; $A - B$ means $A$ is the wife of $B$; $A \times B$ means $A$ is the brother of $B$; $A \div B$ means $A$ is the mother of $B$; and $A = B$ means $A$ is the sister of $B$.
What does $P + R - Q$ mean?