We had a neighbor who lost her husband recently after a 5 year battle with stage IV colo-rectal cancer: http://tonyfellerfund.blogspot.com/
I was diagnosed with cancer while he was preparing to go to Europe to receive treatments not available in the US. His death hit me hard.
But, it's different because his prognosis was poor from the beginning, and they had time to anticipate their lives once he passed. Not that anyone can prepare, but sometimes, I think it's easier to anticipate how you may react.
A good friend lost his wife to a seizure (cause unknown) a few years ago. They did not have kids. They were each other's lives. He was on the phone with her, got off, got home ~20 minutes later, and she was on the floor dead. We also have a former co-worker whose 20-something year old wife went to bed sick one night (flu like symptoms) and was found dead by her husband the next morning - he'd slept in another room to avoid getting sick that night.
Stories like these make us realize how precious each day is and how fragile all of our lives are.
Time is the only thing that heals wounds.
I'd ask her what she needs - she may not know. But, be there for her today, tomorrow, a week from now, a month from now.
If you can do little things like taking care of mowing the yard, running errands, getting gift cards for restaurants so she doesn't have to cook, watching the kids (take them fun places) so she can grieve and tend to affairs, those are the small things that may not be recognized but make a huge impact.
Good luck in helping her transition into her new life. I hope she mourns quickly and remembers him fondly.