Thank you for your question!
Here is what I would say to your friend:
“Dear friend, Accept my deepest sympathy in this moment of grief.
If there is anything that I can do to help during these difficult times,
please let me know. I value your friendship.”
That is all. No need for flowery words neither for a Raja yoga class. Acknowledge your friend’s sorrow and let him/her tell you what you can do to help.