In the case of an unexpected death, use this condolence letter to offer sympathies.
Dear {Recipient},
I am so sorry to hear about the unexpected death of your {relationship}, {Name}. {He/she} was so full of life, and it's hard to accept that {he/she} is really gone. I don't know how I could possible try to comfort you in this terrible time, but if there is anything you need, please feel free to call.
As I'm sure you know, I greatly admired {Name}. One of my favorite memories is of when {anecdote}. It is deeply tragic to lose {Name} so unexpectedly.
I hope to see you soon.
My deepest condolences,
{Sender}