The best thing? Let mama handle this. Besides, us guys don't handle "death" anywhere near the same as the girls do.
Your best bet?
Stand back and left the professional handle it. As they say...
"Been there. Done that."
BTW, if you happen to be FORCED into offering some advice, preface it with "Now, I'm a guy and I can't say that what I'm about to say will be in the ball-park..."
Then...go down hill after that. The sooner you get off the wagon, the easier it will be for you to not try to explain what you didn't really say but they're sure you said it anyway.
Either that, or go for a long walk in the woods and don't come back 'til the bar closes. Both options are painless.