Is it permissible to propose to a girl who has recently embraced Islam and does not observe hijab, without the knowledge of the parents who oppose marriage before the completion of studies, knowing that the parents and sister do not adhere to the commands of the religion, and what is the advice regarding this?

The validity of a marriage is not conditioned upon the parents' approval, but obedience to them is obligatory in matters of good. If delaying marriage does not result in harm to one's religion or worldly affairs, then their obedience is obligatory. However, if you are in need of marriage and are harmed by its delay, then their obedience is not obligatory, and it is permissible to marry without their consent after attempting to persuade them. As for the girl who embraced Islam, she should be advised through your female mahrams or in a way that avoids meeting her, out of fear of temptation. It is also advisable to strive in advising your parents and sister, teaching them matters of their religion, and warning them against neglecting the obligatory duties, especially prayer, while utilizing good dawah methods and supplicating for them.