Q: we have a situation. We dont have hufaz (memorizers of the quran) the shiek we have got injured. He cannot stand and perform the taraweeh salah. Is it correct that he cannot sit if the people in the back are standing?
A: Under ideal conditions, the imaam should try and delegate his responsibilities to the one that is qualified to do the given task without possible confusion to those behind him. It would also get him out of what is viewed as an iktilaf (an opinion that is embedded with difference attributed to its response.) Should such a delegation be impossible as seems to be the case, then in such a situation he can sit and complete his prayer-obligations.
Thus, the Imaam being seated would not invalidate the taraweeh prayers of those behind him that remain in an erected posture whilst he is seated.
Allah Certainly Knows Best.