When combat broke out in the tower, Godwin took to hiding from the battle in a closet. Later he can be found in the Apprentice Quarters near the children. If the Warden sided with the mages, he will return to the second floor (near his original location). If the Warden sided with Templars, he's gone for good.
Godwin is also part of a lucrative blackmarket in lyrium, with most of the trade going to templars who have become hopelessly addicted to this substance.
Godwin is a business associate of Rogek, in Orzammar's Dust Town, who offers the opportunity to smuggle Lyrium to Godwin who is his contact in the Circle.
If after the deal is settled the Warden chooses to tell Godwin of the problems causing the late delivery, he will reveal that he is selling lyrium to the addicted templars. The Warden then has the option of killing him, or blackmailing him. See Precious Metals for details.