Do alms and the recitation of the the Qur’an reach a non-Muslim, and is it permissible to visit their grave?

It is not possible to definitively affirm this man's Islam. To embrace Islam, it suffices to utter the two testimonies (Shahadatayn) with the belief in what "La ilaha illa Allah" (There is no god but Allah) signifies, and disbelieving in anything other than Allah. It is not advisable to give charity on his behalf or dedicate rewards to him. You must sincerely repent for what occurred, transgressing Allah's boundaries in your relationship with this foreign man, for Allah accepts repentance and forgives sins. You must distance yourself from him and not visit him. Occupy your time with what benefits you, such as studying knowledge, reciting and pondering the Qur'an, studying Hadith, the stories of the prophets, and the biographies of the pious predecessors. Seek righteous company that will assist you in maintaining steadfastness, and listen frequently to beneficial religious tapes. If he uttered the two testimonies at the time of his death, then it is hoped that his end was good.