How can one deal with a dentist who has bad manners with women and refuses advice, knowing that he prays, fasts, and performs Hajj?

You should advise the one who abandons prayer gently and wisely, as much as you are able, for the Prophet, peace and blessings be upon him, said: "Whoever among you sees an evil, let him change it with his hand; if he is unable, then with his tongue; if he is unable, then with his heart, and that is the weakest of faith." If an unbearable harm is feared, then the obligation to enjoin him and forbid him ceases, for the Prophet, peace and blessings be upon him, said: "It is not fitting for a believer to humiliate himself." However, you must despise his action in your heart, for he, peace and blessings be upon him, said: "if he is unable, then with his heart, and that is the weakest of faith."