What is the ruling on a father severely beating his daughter to force her to remove her hijab, and is he considered a Dayyuth if he does not do so?

It is not permissible for a father to severely beat his daughter. If a mature or adolescent daughter removes her hijab, her father should instill fear of Allah in her, remind her of the Hereafter, teach her the rulings of Islamic law, command her to wear the lawful hijab, forbid her from displaying her adornments (tabarruj), and prevent her from going out adorned to the best of his ability. A father's abstention from severely beating his daughter who displays her adornments does not constitute cuckoldry (diyatha), especially if it is not out of his رضا (consent or approval).