A person marrying one of his mother's stepdaughters

Q: I am a woman whose mother married after my father's death when I was about a year and a half. I was weaned and my mother bore a son to my stepfather. He then married another woman who bore him daughters too. Is it permissible for my son to marry one of these girls? Appreciate your guidance, may Allah guide you!

A: If the matter is as mentioned, it is permissible for your son to marry one of your stepfather's daughters from his second wife, for she is not among the unmarriageable women. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.