A long time ago, a colleague of mine was killed in a plane crash. She left a husband and young son. I kept in touch with the husband for a few years but I relocated, married, had a family and made a new life for myself. My colleague's husband never got over the loss and all we had left in common was her memory. The tenth anniversary of her death is near. I lost touch with him and while I don't want to rekindle our relationship, I would like him to know my colleague is not forgotten.

Buy a lovely thinking of you card and write a short message. Tell him, "I
am thinking of you, (insert child's name) and (insert colleague's name)
today. I want you to know that I will always remember (insert colleague's
name) and will continue to keep you and (insert child's name) in my
thoughts and prayers. Choose a complimentary close that you are comfortable with, for example, sincerely or with best wishes.