When writing your message, keep in mind the recipient may be feeling especially vulnerable and sensitive. Avoid clichés like “Time heals all wounds.” Do not include personal “news” or explanations about what is going on in your own life. Unless you know such remarks would be welcome, avoid spiritual, religious or philosophical statements.
Sympathy cards should be sent to the family as soon as possible, ideally within one week, two at the most. If desired, a longer condolence letter can follow. Homemade cards with meaningful photographs, illustrations, or poems are also acceptable. While e-mail cards and notes are acceptable, a sympathy card or a handwritten letter is usually preferred. Never enclose money in a sympathy card.
Some are doubtful over whether they should send a sympathy card at all. The consensus seems to be that it's perfectly permissible to express sympathy to anyone you know who has suffered a loss.
Some may hesitate over sending a sympathy card when business relationships are involved. The general view in this situation is that if you want to express sympathy to someone who has suffered a loss, do so. Sending a sympathy card shows that you care, are mindful of another’s pain, and are willing to offer what comfort you can.