Is she wrong in seeking divorce, alimony, and her marital belongings after discovering her husband's drug addiction and his infection with Hepatitis C, her mother-in-law's mistreatment of her, and her husband's failure to provide for her?

We advise you to give your husband one last chance, reminding him of his duty to Allah and the necessity of repenting from addiction to evils that corrupt both religion and worldly life. Remind him also of your rights upon him regarding maintenance, an independent dwelling, and ceasing to harm you. If he does not respond, then there is no objection to seeking a divorce. If he refuses, then take the matter to court to secure your legitimate rights.