Atheism is untenable in the 21st Century
You are giving him way too much credit. He isnt being stubborn, that would require him having an actual position to cling too, which he doesnt. He THINKS he does, and thats why he cannot engage. He has been programmed with placeholder words that have no substance and thus anyone actually trying to engage with him is just firing off into thin air. He has nothing to offer, so there is nothing to hit with any point you might want to make.
That, and there is this underlying immaturity to his comments which make it easy to think of him as stupid, or a troll but thats not what it is. He is a victim, made vulnerable by his own childish fears and fragility. Its not really his fault, which I think is why he gets people trying to help him. It is folly however, as part of his delusion is a defence mechanism where he ridicules the things he doesnt understand. He HAS to do that, he HAS to put in those dismissive responses and “LOL”’s, because his entire view is based on a childish narcissism of self importance. He’s this special guy, with a special little view that his philosophical opponents are powerless to respond. Again, that is the exact opposite of the reality. Unsurprising, since thats basically what religion is all about, denying reality for comfort.