Is it obligatory for a woman to stop working in a mixed-gender school—there being no other option—in order to help her parents, especially if the suitor dislikes her work?

There is no objection to the wife stipulating to the suitor that he permit her to work, and he must fulfill this condition. The wife should balance work with managing the household, and it is sunnah for the husband to assist her in this. It is not permissible to work in a place where there is prohibited intermingling, except out of necessity or a need close to it. The wife's maintenance is obligatory upon her husband, and she is not obliged to work to support herself.