Is a person who exhibits contradictory traits—such as lying, mocking, refusing to apologize, being able to convince others they are wrong, attempting harassment, and demonstrating inconsistency between their words and actions regarding religious commitment—suitable for marriage to one's sister, or does their personality indicate hypocrisy?

The young man mentioned is involved in great abominations, including lying, which is one of the major sins and a characteristic of hypocrites. It is strange that you would associate with a man possessing these traits. Even stranger is that he is given free rein to sit with the sister, be alone with her, and ask to touch and kiss her. This is an abomination from which one must repent and protect the sister from temptation. If he desires to marry her, his desire does not justify his actions, and he is not worthy of marrying her due to his unsatisfactory religious commitment and character. If you are her guardian and you marry her to him, you would have betrayed the trust.