What do you Say?

Not good news for my boss today, close family death. What should I say to him?
It's not like he's a close friend or a family member who I could have hugged, cried and reminisced with. I only know him through the professional working 9 to 5 that we share... I didn't even know he had a sister, let alone one married with a six month old daughter (I'm not one of those work colleagues that tells you your life story in the first ten minutes that you meet them, nor do I want you to know all of mine).
My boss is going through the loss of a friend, a husband to his sister, father to his niece, and sharing that loss with his family, all in another country. All I can offer is that I have suffered a family loss before, and can only conclude he is going through similar emotions that I had...
So all I could think of was sorry for your loss - the most simpliest, though the only appropriate sentiment that can be made... still felt like an inadequate putz though!