They are protective of Dohu, but they also want him to conform to the norm in society. Like his sister insisted that he had to look presentable rather than the one Dohu most comfortable with. Dohu's family has a lot of influence on him such as he always keeps his room clean and he celebrates birthdays. While they are definitely close, Dohu doesn't truly open himself up to them as he kept his bullying and Juheon's existence a secret from them. Perhaps part of it because he doesn't want them to worry about him. It could also be because he doesn't like being pressurized to conform to the norm.

Why do I feel like we know nothing about Dohu snd his family