"No amount of money or meaningful words could ever describe how much we appreciate you.  You are one of a kind and irreplaceable.  Anyone who is lucky enough to have you in their life is beyond blessed.  We could write a 10 page letter of all the things you have helped us overcome, but we won't do that.  We love you and hope to have you in our lives for many many years to come.  Thank you for being a mother, friend, and a person who speaks wisdom and truth into our lives."