Helping with a friend's loss of a parent

Catherine
I wasn't sure where to put this but I thought adult relationships might be the place. Let me know if it's not! 
My friend's partner just lost his father last night unexpectedly. I had never met his father personally but I know that that is a huge and monumental loss for him and his mother. I would love some ideas to help them through this as I have a lot of time on my hands but no idea what would help or hurt. Does anyone here have any ideas on how to support someone who is going through this?