All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Brawelvi sect is an innovative Sufi sect that originated in the Indian sub-continent during the British colonial era. The innovations practised by this sect are innovations that take a person out of the fold of Islam. They believe that the Prophet is an absolute vicegerent of Allaah in the Universe and that he has full mastery of it. They also believe that the allies (i.e. the most pious and righteous people) who come after him inherit such mastery. They urge their followers to seek refuge with Prophets and allies. They consider anyone who opposes their beliefs as apostate.
They build graves and they worship them beside Allaah, and they offer vows to them, and circumambulate around them. They also do many other acts that take a person out of the fold of Islam.
Therefore, if your husband is a follower of this sect and believes in their innovations, then he becomes a non-Muslim after establishing the evidence against him (i.e. after clarifying the truth to him and he refuses to follow it). So, you are obliged to separate from him and ask for divorce. As regards your children, they are Muslims because the children follow the best religion of the two religions of their parents. In case he had already divorced you, it is not permissible for you to return to him because of the reasons which we have mentioned unless he repents and leaves this sect and its beliefs.
Allaah Knows best.