Pretty much that holiday will forever remind them of their tragic ordeal. Very sad. Here is a link that may help.
Suggestions for someone grieving during the holidays:
http://www.death-dying.com/articles/article.php/artID/200017 or
http://tinyurl.com/vzkt6 (use the tinyurl if you can't paste the longer link into your browser. they both go to the same place.)