Is a son considered undutiful (disobedient) if he refuses to return to his father's house, as the father had expelled him to force him to marry someone he does not desire, and the father now wants him to pledge allegiance to him (swear an oath of obedience) not to disobey him in any matter?

The father does not have the right to force his son to marry someone he does not desire, and obedience to him in this matter is not obligatory. The son is not considered disobedient for disagreeing with him on this issue. However, the son must visit his father and treat him kindly to the best of his ability, for the father's right is great and is not forfeited by his injustice.