Desiderata

Of course I think elder sisters like Zhang Zifeng starring in the movie should raise their little siblings in that circumstance. As they are bonded by blood ties, and the little boy has no one to rely on, the duty falls on his only sister.

If it is difficult for her to raise her little brother alone, then she can apply for government aid. She also wants to take undergraduate exam, though there is a tough situation for her to do that, she could ask for delay the entry for a year to find a way out for both of them.

Asking help from government or other relatives are good options. If she just throws that duty away, then what will happen to her little brother is unimaginable. Everyone has certain roles - daughter or son, sister or brother, mom or dad, these identifies come with a duty that you must take.