Is it permissible to ruin my sister's abaya to curb her adornment, knowing the harm that might result from that?

The path to commitment is not easy. You must be patient and offer good counsel to your family. The fundamental principle is that a woman has authority in her home, and her parents do not have the right to force her to work. If the work does not contradict Islamic law and does not affect your faith, then you may work to be dutiful to your parents, while being careful to choose jobs suitable for women. Advise your brothers with gentleness and kindness, and it is not permissible to damage your sister's abaya, as that will not change the wrongdoing. Increase your supplications for their guidance.