What is the ruling on dealing with a neighbor who does not pray, drinks alcohol, and beats his wife, given the fear of advising him?

What your neighbor does—drinking alcohol, not praying, and beating his wife—are grave Munkarāt (reprehensible acts). You must denounce them to him, advise him, and call him to Allah. If you cannot do so alone, then seek out someone from among the righteous to accompany you and support you. If he does not respond, then refer the matter to someone who can deter him and stop his evil. If no such person is found, then you must shun him and denounce his actions in your heart, for the Prophet, peace and blessings be upon him, said: "Whoever among you sees a Munkar, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith."