بسم الله الرحمن الرحيم
(Fatwa: 288/223/L=3/1438)
If the Barelvi Imam does not carry the belief of kufr and shirk then salah is valid behind him with karahat (certain degree of undesirability). However, if the imam of some nearby mosque follows the sunnah and avoids the bida’h, then it is mandatory to offer salah behind him. Our elder Ulama have not absolutely declared the Barelvi kafir or mushrik, hence when there is no other mosque nearby then it shall be allowable in compulsion to offer salah behind a Barelvi Imam.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband