Is the niqab obligatory, and is this young man righteous, and is it permissible to obey his commands to quit studying and wear the niqab despite the family's opposition, especially with the strictness regarding the hijab in studies?

Scholars differed regarding covering the face and hands, but covering the rest of the body, such as the hair of the head, is obligatory. If a young man of good character and religious commitment proposes, he should not be rejected with flimsy excuses, as the Prophet said: "If someone whose religion and character you approve of proposes to you, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption." Try to convince your family to accept him. Marriage is not valid without the guardian's consent, and there is no obedience to a creature in disobedience to the Creator. Therefore, the hijab (definition) is more prioritized if the school prevents it.