What is the ruling on a foreign male teacher remaining alone with the sister after her brother has left to perform Maghrib prayer, and what should be done in this situation?

We have previously clarified the regulations for a man teaching a woman in a private lesson. If these regulations are met and your brother is aware, then seclusion is negated by his presence. This is conditional upon the absence of temptation and suspicion; otherwise, it is not permissible. It is preferable that you seek a woman to teach you. If you are in dire need and can only find a man to teach you, and the teacher is unwilling to go to the mosque for prayer, and your brother fears for you, then let him pray at home with a congregation. He is excused then from abandoning the congregational prayer.