How Ought I Respond to a Christian-Turned-Atheist?

On Friday night, Justin Vollmar, a self-proclaimed preacher of the “Virtual Deaf Church” Facebook group, released a sub-titled video blog (“vlog”) declaring his departure from Christianity to Atheism. As he explained in the vlog, it marked the “culmination of four long years struggling with contradictions in the Bible and with Christianity.” He blatantly rejected the cardinal doctrines of Christianity (i.e., the Trinity, Jesus as the Son of God, the authority and veracity of the Scriptures, &c.). Near the end, he has declared his intent to create additional videos to attack Christian doctrines so that people can be freed from “the shackles of religion,” as some Atheists might describe it. He also joined the Clergy Project, a support group for 556-plus active and former professional clergy/religious leaders who have renounced Christianity.