I persuade the proof from Idolaf Battle-Born. Now i want to return it to Avulstein. His house is locked all the time and he never leave it (or he does?). When i pick the lock he is angry and ask me to leave the house and cannot talk about the quest. My calm spell is too weak for him. Maybe he is angry because i spoke with Idolaf? Is the house ever opened or he ever leaves it?

Try getting the information from Jon or break into the house to get the info.