A useful condolence leaves the grieving person free to answer briefly or not at all.

A message that asks for a reply hands somebody a task at the worst moment. Questions about how they are coping, offers that need a decision, invitations that require an answer, all of it adds to a day that is already more than they can hold. The kindest note carries its own ending. It says something true and then closes without waiting.

Write to say you are thinking of them and that no answer is needed, and mean the second part. Mention the person who died by name if you knew them. If you offer something, make it specific and easy to accept or ignore.