السلام عليكم ورحمة الله وبركاته We study several books with a teacher who follows the way of the Salaf and the correct manhaj. Out of humility, he dislikes being called “Ustadh.” What would be the proper etiquette in this situation? Should we avoid the title completely or only in his presence?

Yes, do honor your teacher and call him Ustad. Of course, he will say so out of humility because, in his eyes, he sees himself as nothing. If he is someone who is truly knowledgeable, call him Sheikh as well. Subhanallah, we see the people of Bida really boosting their teachers and du'at. Even if they were not knowledgeable, they would say they are scholars and so on. Sometimes we see some of our Salafi brothers belittling their teachers, despite the fact that their teachers are so much more knowledgeable than those from the people of Bida; they are worlds apart in knowledge. Subhanallah, they are more deserving of being honored and respected.