There are times, when even "Super Wife" can't do everything. And now is one of those times. My father-in-law passed recently, and my husband has been dealing with it very well in my opinion. I'm trying to be around without crowding him, just to let him know that I'm available when and if he needs to talk. However I cannot be everything, namely in this instance his father.
The other night we were just sitting in the family room, he working on the computer, I rocking the baby; and he says - "I miss talking to my dad, he was really great to talk to." There is nothing you can say in that moment. You can't counter with, "you can always talk to me", it doesn't fit. It's almost trite. All you can do is empathize, maybe offer a hug, and encourage your loved one to remember the greatness in the one they've lost.
The truly frightening thing, is not knowing how to comfort the people you love, when they are in this type of pain- deep emotional strife. There is no "feeling better" at least, not for awhile. Your only hope is that they can get some sleep, play with the kids and see the love around them and not dwell on the pain.
Unfortunately, now this is Life As I Know It.