Question:

There is a minor (non-baligh) boy who is a hafiz of the Quran. The minor after taking precautions concerning purity joins the salah. Will there be any deficiency in the salah of the imam if this minor corrects him? Will the salah become invalid or not?

Answer: حامدا ومصليا ومسلما

The minor that is near maturity can take the responsibility of listening (and correcting) the imam in taraweeh. Rather if there is no other listener, then he can even be placed in the front row.

 Allah Ta’aalaa knows best.
Hazrat Mufti Ahmad Khanpuri Saheb (May Allah preserve him)
Mahmoodul Fataawaa 1/489