Above all, show your love. Show up. Say something. Do something. Be willing to stand beside the gaping hole that has opened in your friend's life, without flinching or turning away. Be love. Love is the thing that lasts.
Grief is uncomfortable. It is foreign. It is an ill-fitting garment that pinches you in all the wrong places. You can feel like you've shed it for a while, and then it can unexpectedly wrap you up like an unwanted sweater in July.