Falling Asleep during the Final Sitting

Q: Salaah-209: A follower fell asleep during the final sitting of the Taraaweeh salaah and woke up only when the Imaam made the Salaam. What is the ruling?

Answer: In the stated case, his salaah will be valid if he recites the Tashahhud after the Imaam makes Salaam and then makes his own Salaam.

Fatawa Rahimiyyah vol.2