The Gospels were written down in Greek, which is an inflected language, so check out the gender of the pronouns in the original and translate accordingly.
That said, it sounds like the substitute priest is one of those light in his loafers heretics. Keep him away from the altar boys, IMHO.
I would know, I think, if he did anything wrong that way, because a friend of mine belonged to his parish.
There are many other ways to offend God, though.
Also, only created beings have sex. God and the Holy Spirit have no sex, they are spirits, not flesh. God was incarnated as a man in Jesus Christ for certain reasons, and it’s also natural to refer to God as He since fatherhood is a better metaphor for God’s relation to us than motherhood. But that does not mean that God is a man any more than He’s a woman. Those are limited categories. God, by definition, transcends all limits.
In Greek, the word for "Spirit" is neuter (to pneuma), but there are three pronouns in the Greek text referring back to the Spirit, all of them masculine--ekeinos twice and heautou once. The feminine forms have different endings.
BTW, what is “inflected language?”
The Holy Spirit as “she” comes from the book of Wisdom, where wisdom is seen as female and is associated with the Holy Spirit.
God is beyond female and male, but his relationship to us is that of a father (male), the parent who guides his children.
But there are biblical references to God holding his people and comforting them like a nursing mother comforts her child. So there is a feminine idea there too.
The problem is not using the feminine per se as that we live in a country who is determined to destroy masculinity and femininity in all things, including in the church.