Q: What is
the ruling on the wife's uncle who is a half-brother to her father, especially that their ages are close? Is he considered a Mahram (unmarriageable relative) to her like an uncle who is a full-brother to her father?
If he is not a Mahram to her, is it permissible for him to marry her? May Allah reward you best!
It is unlawful for a man to marry the daughter of his half-brother. Allah (Exalted be He) says:
Forbidden to you (for marriage) are: your mothers, your daughters, your sisters, your father’s sisters, your mother’s sisters, your brother’s daughters
A brother may be a full-brother or a half-brother whether from the side of the father or the mother. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.