That's the trailer for Our Friend, a movie based on the true story told in this Esquire article by Matthew Teague: The Friend: Love Is Not a Big Enough Word.
His wife was just thirty-four. They had two little girls. The cancer was everywhere, and the parts of dying that nobody talks about were about to start. His best friend came to help out for a couple weeks. And he never left.
I remember very clearly that essay and the day I read it — I think about it all the time. I don't know if the movie is going to be any good (I hope so), but if you've never read this essay, carve out some time to do so today.