In the traditional view of the older generation, young men are seen as frivolous, irritable, and in need of care. Men who are slightly older are considered mature, stable, and better at taking care of others.
If Dang Yang really gets together with his sister, their parents will surely worry whether young Dang Yang can care for and tolerate his sister's bad temper.
In short, if Dang Yang is just a neighbor or an ordinary junior, their parents will surely like him very much, but... if Dang Yang wants to be with his sister and become their son-in-law, the parents are bound to be picky about Dang Yang.
Firstly, the age factor – while it's not necessarily a deadlock, at least the parents will care about it.
They will worry that the young Dang Yang is unable to take care of his sister and may even suspect that his desire to be with her is just a child's sudden interest, which will pass and leave the sister ignored.
