Do you have any good advice for helping loved ones through tragedy?

My husband’s best friend had a baby girl a few weeks ago. She was born with a heart problem that they knew about, but were told was manageable. It turns out that it was not and they lost her today. My heart is broken for them; our little girls were supposed to grow up together; I can’t even imagine what they are feeling.

What do you think is the best thing to do for people you love who are grieving? Physically be there? Give them space? Bake them something? I am at a total loss.