Miriam H. answered 08/07/19
Multilingual Yale grad Hebrew and English tutor, 30+ years in Israel
Not sure he is correct, and even if he himself might say בנות when talking about women, that doesn't mean that the women would like it. It probably depends on the social class of the women and where they live.
Just as in the U.S. some women would say they went out with the girls, in Israel it is fairly common to use בנות to refer to grown women, though I think it's more something women call each other.