Thats a type of what we call shin bang. It isn't the boot. Hot spots on a boot will be toes, side of foot, arch, etc. 
She's using boots that are too big and buckling the ratchets on the calf too right and the foot to loose. Heel is sliding through the footbed creating a pressure point along and across the shin.
She needs to mondo down. Buckle ratchets 2/3 as ti get as possible but only ratchet the top to snug/fit not tight.
We she has the boot on, her toes should he touching the end of the boot. You want it that tight. You want no Space between toe and boot. It won't be comfortable until you get on the hill.
You need to know the mondo WAY before you buy a boot and try to mold it. Also NEVER use the online calculator. Please please please don't. Meaning, you really gotta try the boot on in person and in a State w a ski hill that has more than 2000 vertical ft pref a town about 5/6000ft.
Trust me.
Once you find the mondo you will want to find a Stiffness/Flex - R value - they range from 130/40 down to 60. She probs wants something in the 75/90 range.
Once you find the boot w the R and the right mondo, you can move into the internals of the boot. Thats where you'll get the foam/cork molded liner, foot beds, splints, etc.
First you gotta find the size then the Flex then the boot -
If you're going Surefoot they're almost all Lange IIRC. If you're going to a boot fitter then they can scope any hard shell. Just depends on what you want - one stop shop or buy from outside and bring in for fitting.
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