What is the ruling regarding a Muslim who excommunicates his brother for abandoning prayer while denying its obligation?

Whoever abandons prayer, denying its obligation, is an infidel and outside the fold of Islam, by the consensus of scholars, because he has disbelieved the Qur’an and the Sunnah, and denied what is known to be an essential part of the religion. Therefore, whoever declares someone an infidel for abandoning prayer while denying its obligation has hit the mark. He should explain to him the danger of apostasy and its punishments, and invite him to sincere repentance, seeking forgiveness, performing righteous deeds, and associating with the righteous, all with wisdom, good admonition, and compassion.