With diabetes, particularly if the person with diabetes has high blood sugars (normal blood sugars for non diabetic
persons are typically
in the range of 70 -120, and mostly
in the 80s and 90s), there can be many problems.
These include poor circulation, neuropathy (nerve pain), muscle damage, at worst even ulcers that do not heal.
See a podiatrist is a good start. Your friend definitely needs to take good care of her feet.