After a friend or relation has died of a long illness, this condolence letter can provide some comfort.
Dear {Recipient},
I recently heard that the sad day has finally come and {the deceased} passed away. Even though I knew it was coming, it was still horrible to hear. I am terribly sorry for your loss, and I cannot imagine your grief.
Even though {the deceased} kept fighting until the end, I take solace in the knowledge that {his/her} fight is over and rest has finally come. If there is anything I can do to assist you in this hard time, please contact me at {phone/email}.
Again, I am sorry for your loss.
Yours always,
{Sender}