With the understanding that she's leaving them as messages of hope for her parents after she passes away? A little.
There probably are 6-year-old children out there who understand the concept of death in terms that the world will go on turning without them, and their parents will have to find a way to go on with their lives, but the odds of one of them
also dying of brain cancer and being the most lovely and photogenic girl a camera can ever ask for... well, the odds are pretty low. Seriously, this is what fiction is
literally made out of.
I think they're fudging the facts some, but if it's in the interest of funding brain cancer research for children I honestly don't see the harm.