Is it permissible for a man's aunt (his mother's or father's sister-in-law) to teach Tajweed and Qur'an memorization to a young non-mahram man, even if her own son is present?

One should seek a man to teach the Quran, even if it requires going to him at a memorization school or his home. If that is difficult and the only option available is to learn from the paternal aunt's husband's wife, then it must be from behind a veil, and in the presence of her husband or a mahram (definition). The mahram must be a person of standing, have reached adolescence, and his mahramiyyah must be permanent, like a son.