The beginning of chapter four begins with Asher drawing Stalin dead in his coffin many times. I don't think Asher realized the seriousness of what he was drawing. His father, however, considered these drawings to be extremely disrespectful to him. He began to think that Asher's drawings were detracting from his studies, especially from the Torah. I think Asher sensed his father's disappointment because later in the book, he sacrificed the time usually spent for drawing and devoted it to studying the Torah instead.
It is also discussed in this chapter whether or not Asher will go with his family to Vienna so Asher's father can continue his work with the Rebbe. Asher is not very fond of this idea, however, his parents desperately want him to go with them. Asher looks for other alternatives so that he could stay in Brooklyn and his parents could move to Vienna. He makes reference to leaving his street. This now leads me to believe that it's not Yudel Krinsky that Asher is afraid to leave, I think it's his street. I think he is scared of change and feels most comfortable in familiar places. At the end of chapter, however, Asher goes with his parents to get passports. He obviously feels that he has no choice in whether or not he will go to Vienna with his parents.
Also in this chapter, Yudel Krinsky helps Asher with his art. He poses for Asher in between customers. He also provides Asher with a spray that prevents the charcoal from rubbing off the paper. Yudel also attempts to boost Asher's self-esteem by telling him that he has a gift and that he should keep it. This is probably why Asher chooses to spend time with Yudel. He makes Asher feel good about himself, and his parents don't provide that support.