A bit of an Aunt Sally there with your self-styled atheist. I haven't met an awful lot of atheists who want to put up arguments that disprove God, to be honest. The sheer illogicality of God is that he has been invoked to explain a complex universe whilst being far more complex and inexplicable himself than the thing he's supposed to be the explanation for. It hardly helps that, in order to exist, he has been excused all the rules of physics and the need to have any evidence for his existence. This particular self-styled (what IS that anyway?) atheist has concluded that, from all this, the chances of his existing are vanishingly small, but I really can't be arsed to try to disprove his existence, either to myself or to anyone else.