How should I deal with my father and brothers who do not perform the prayer and curse the Divine Being and the religion, and is it permissible to tell people about that?

Your father and brothers are in grave danger because of their blasphemy against Allah, His Messenger, or the religion, which is apostasy that expels one from the fold of Islam. Abandoning prayer is a grave sin; indeed, many scholars consider it an act of apostasy. You must advise them gently and kindly so that they may repent. If they do not repent, treat them as you would disbelieving relatives, with kindness and good companionship, especially your father, in accordance with the Almighty's saying: "But if they endeavor to make you associate with Me that of which you have no knowledge, do not obey them but accompany them in [this] world with appropriate kindness." There is no harm in informing someone who can deter and restrain them from such actions.