My kids are much younger, so I have not had to deal with this yet, but I know that the day will come that I will tell them the same story that my mom told me.
My mom was in a big family, number 9 out of 10, and one year when she was about 6, her dad had a stroke. She remembers that her mom and dad told her that sometimes santa could not make it to all the houses, but that did not mean that he did not care about her, or that she was not a good girl. She told them don't worry Santa won't forget. That night after she went to bed her parents and older siblings worked very hard to "make" something for the younger ones, when there was a knock on the door. It was 4 men from the area bearing gifts. They brought ham, sugar, potatoes, bread, candy, clothes, and of course they brought toys for all the kids. She said that it was the best Christmas ever. She said that when she was my age and asked her parents if Santa was real they told her the story and told her to decide for herself. She told me that she still believes in Santa and all that he stands for.
I know it must sound sappy, but I am like my mom, I still believe in Santa. Now I know that there may not be an actual man in a red suit and sleigh flying all over the world to deliver the gifts, however he lives on in each of us.
I hope that my children will alway believe in the legend, and the things that it has taught us about being nice to one another, and showing compassion and care for others.
I don't know that this helps, however it is something that has really stuck with me.
Good Luck,
T.