This morning on the news the father said with the radiation treatments it would do damage to her spine's ability to grow and therefore his daughter "would stay short". It seemed like he was saying this was a factor in why they didn't want her to have more treatments. No doubt, having a sick child is the worst. It's an enormous strain on a family.
Short girls are a problem for some people.
Better 5'1'' than six feet under.
As humans, when emotions run high in decision making situations, it's usually very difficult to make a rational decision. Having seen many situations such as this (professionally), the way I would approach it would be that the spine not growing is secondary to killing off the cancer cells. If you die, your spine won't grow any more; if you get the radiation and live, your spine will still grow, but maybe not as much as under normal circumstances. Sure, easy for me to say as I sit here at my computer, but I am confident that I would say the same thing if I were in the same situation (hopefully I will never be in that situation).