Here are 10 tips on how to write a condolence letter and what to say and what not to say. "I'm deeply sorry for the loss of your mom, you're in my thoughts and prayers." "Let me know what I can do for you. " "We would like to express our sincere condolences to you and your family. Keep the letter as brief and as short as possible. We are here for you and send our deepest sympathy to you and your family. In loving memory of your mom. "I am deeply saddened to learn that your (mother, father, spouse, sibling, etc.) recently passed away. Please know that you have my deepest sympathy. "The loss of a mother leaves a void that words cannot fill.