Does divorce occur if the maternal uncle enters his sister's house after the father, in a state of anger, said, "The Haram (forbidden/unlawful) does not want to enter my house"?

The predominant view regarding swearing by something forbidden (Al-Haram) is that it depends on the intention of the one swearing. If he intended divorce, then it is a divorce. If he intended ẓihār (a form of divorce by likening one's wife to a forbidden relative), then it is ẓihār. If he intended an oath, or did not intend anything specific, then it is an oath.

If your father did not intend divorce or ẓihār by his oath, then he must offer expiation for breaking an oath if he breaks it. The oath is not broken merely by your uncle entering the courtyard of the house, unless your father intended to prevent him from entering the entire house, including the courtyard.

We should point out that swearing by something forbidden is not legislated. The legislated way of swearing is by Allah the Almighty.