Can't find the words

My friend's dad died today. I hadn't talked to him since Thanksgiving. I knew the situation was grave but I guess I didn't know how grave. As soon as I found out, I called him. I just didn't know what to say. His voice sounded small and sad. I consider myself very lucky. I have a lot of friends who've had a parent (or both) pass away. What do you do for your friends? I mean, he lives 500 miles away. I can't go to the funeral. Do I send a card, flowers, what? He was grateful that I called; I could hear it in his voice even though I didn't have much to say. He is one of my best friends even though we don't talk that often. I'll see him when I'm in MD for Memorial Day but I still don't know what to say.