A person in distress

An acquaintance of mine married a woman from the land of Israel.
In his father-in-law's Judaism, the girls are to have a permanent baldness before baptism and not to eat machine-made matzah, and a few other religious principles such as this:
Oh, and nothing more.
After a few children, the old man learned the subject.
And they came to the conclusion that there was no need to shave before baptism, and his wife was happy to get rid of something that was very burdensome and humiliating to her.
But she can't come to her father's house for fear that her hair will grow out, so she only comes with a wig, which is cumbersome and uncomfortable.
Recently, the father started coming to their house unannounced.
Just knock on the door.
He enters, takes a drink out of the fridge, stands and shouts, "How can you drink such a drink with such a screwed-up kosher?" (strictly, but not strictly)
And she ran to the room to change into a pub so that he wouldn't see a man who wasn't a priest according to his religion.
 
What can be done about such behavior?