What should a husband do whose hatred for his wife escalates after her vulgar accusation against his mother, given that they have a daughter and her mistreatment of him continues?

If the situation is as you have described, then you are not to blame for divorcing your wife. However, it is better not to despair of reforming her and striving for reconciliation between her and your parents, for perhaps Allah will place much good in her for you, as Allah Almighty says: "And live with them in kindness. For if you dislike them - perhaps you dislike a thing and Allah makes therein much good." (Quran 4:19). And as the Prophet, peace and blessings be upon him, said: "No believing man should hate a believing woman; if he dislikes one of her characteristics, he will be pleased with another."