Is it permissible to avoid dealing with a neighbor who does not pray and curses religion and the Lord, except for the minimum of rights such as offering greetings and responding to a sneeze, given that he is poor and the Muslim is well-off, and would that be considered arrogance?

Whoever curses Allah or the religion of Islam has committed an act of disbelief (kufr) and has apostatized from the faith, by scholarly consensus. The rulings of apostasy apply to him: he is separated from his wife, his slaughtered meat (dhabihah) becomes unlawful, and the ruler must execute him if he does not repent. He is not prayed over, nor is he buried in Muslim cemeteries, nor does he inherit or bequeath. Scholars have explicitly stated that whoever curses Allah or mocks Him, His verses, His books, or His messengers has committed an act of disbelief. It is not permissible to show kindness to such an apostate; rather, his case must be referred to the judge or the ruler.