Well that is completely wrong. There is common agreement that it is impossible to prove there is or isn't a god, regardless of whether you are atheist, agnostic or believer. That's the one thing they all agree on!
That's rubbish. Who is he to tell anyone what they have to believe? I could be atheist about God, a true believer in unicorns, but agnostic about pixies. I may have formed these opinions based on my own observations and experiences.