The Bible says that there is no joy in Heaven at the death of the wicked. So when Hitler died, God and His angels didn't jump up and down for joy.
So if we aren't supposed to celebrate when someone wicked dies, how much less should we do so when someone who is not wicked has trouble. Jesus said to pray for your enemies. Pray that they find Him. Paul was once a mass murderer, and he turned out to be the greatest of all Christians. Moses beat a man to death with his fists. David killed a woman's husband, and took her as his own. My point being, anyone can be turned around.
Even Osama Bin Laden has a chance- as long as he still breathes. A chance to live. God doesn't care what you did before you find Him. He cares what you do afterward, though.