What is the ruling on performing Taraweeh prayer behind an Imam who does not recite aloud after Al-Fatiha, and prays Shafa and Witr like Maghrib with the Tashahhud after the second Rak'ah, and says "Allahu Akbar" twice in one of the Rak'ahs before Rukoo', and does not supplicate with Du'a Al-Qunut? And must the congregant follow the Imam if he makes a mistake in the number of Rak'ahs?

Scholars differ on the audibility of saying "Amin" aloud in congregational prayers where recitation is audible. The more correct view is that it should be said aloud. It is permissible for a congregant to say "Amin" aloud behind an Imam who says it silently, provided no harm results from it. The description of the Witr prayer mentioned is according to the Hanafis, where the Imam pronounces the takbir after the recitation for the Qunut and then for the ruku'. Following him in this is permissible. As for supplication after the 'Isha prayer, it is legislated individually, not congregationally. Their not supplicating in Witr does not prevent praying behind them, because Qunut in Witr is a Sunnah. Your husband should not miss the virtue of night prayer with the Imam because of this. Intentionally following the Imam in a third rak'ah of Tarawih is not valid. The congregant who is certain of the mistake should not follow him; rather, he should sit for the tashahhud and say salam, or intend to separate from him. As for one who is in doubt, he should follow him.