What is the optimal course of action with a mother who works in tailoring abayas that might be contrary to Sharia, knowing that the questioner supports his mother and works as a government employee?

The conditions for the permissibility of a woman's attire were previously explained. If your mother's work involves forbidden clothing, advise her gently and kindly, and be dutiful to her. As for her money, if her work is unlawful and her salary is her only means of income, then it is not permissible for you to eat from it, drink from it, or live in a residence acquired through it, as long as you are self-sufficient with your own salary.