Is demanding the right to establish the claim of a son who contributed significantly to building his father's house considered an act of disobedience to parents (ʿuqūq), especially after family disputes that led to the expulsion of his wife and children?

Your demand for your right is not considered disobedience to your parents. Al-San'ani said: "Likewise, if, for example, the parents owe a debt to the child, or a legitimate right; and he takes them to court, that is not considered disobedience." However, you must be dutiful to your parents and accompany them with goodness, for being dutiful to them is one of the best acts of drawing near to Allah and a cause for success and prosperity.