I really used to love Bill Maher a few years ago. I know that the majority of Catholics who use this site are politically conservative and so it's likely that most people here have never liked Bill or any famous liberal for that matter. That's ok, I'm not here to debate politics. I just find it so sad that Bill feels he has to wage this war against faith. With his horrible film Religulous and various attacks like the one mentioned above he has declared war on all faiths.
I know he's been an atheist for a long time, but I never had a problem with him having his own personal beliefs. So he's an atheist, that sucks for him. If I were a friend of his I'd try to gradually and gently persuade him that he's mistaken, but since I don't know him I can't try to convince him of his error. But now he's gone from atheist to militant atheist, he's become a faithless version of the people he despises so much (radical fundamentalists). Instead of being content to let others believe as they will he feels compelled to attack faith at every opportunity relying on lies and exaggerations to achieve his goals. It's very sad.
At the same time I do hold out a sliver of hope that his rage is that darkest hour before the spiritual dawn for him. I've noticed that most of the time it's the people who are indifferent about religion who are really lost and hardest to reach. But those who rail against it, those who fight with you do have feelings about faith, even if for the moment they hate it. These people are more open (whether they know it or not) to finding God than people who simply go through the motions with no thought or feeling or are so indifferent that they don't even bother with the formality of going to church anymore. Just look at C.S. Lewis for instance, who rebelled against God for so long only to become one of the most famous Christian apologists of the century. He was converted from being cold to being hot, not from being lukewarm.
With that said, I won't hold my breath waiting for Bill to find God and repent. However, what I will do is pray for him. Maybe you could too? The Lord asks us to pray for those who persecute us. Who knows, maybe our prayers will make the difference?