Is it permissible for a husband to shake hands with his wife’s father’s wife?

The questioner : Is it permissible, as you say, for a husband to shake hands with his wife’s father’s wife?

The Shaykh : No, it is not permissible for a husband to shake hands with his wife’s father’s wife, and it is well known that his wife’s father’s wife is not his mother. However, if he shakes hands with his mother, there is nothing wrong with it, because the wife’s mother is a mahram (a relative one may not marry) to the husband. Yes.

The questioner : May Allah reward you.