This is a perennial question - can an atheist be good? My answer: they can only appear to do good things if we lower the standard for what we call "good."
Atheist, Christopher Hitchens, taunts Christians with the question, "Name one good thing a Christian can do that an atheist cannot."
Atheists can commit their lives to helping the poor, needy, and downtrodden, even "surrender their body to be burned" for their fellow man (i.e. "be good"), but they cannot fulfill the highest moral imperative - worship God. Apart from the Agape love of the cross, the highest love of man is but a better hate - and not really "good" at all.