The podiastrist had me take x-rays, then adviced me to change the kind of shoes I worn. He also sold me some pricy salt to wash my feet - 4X the price from a regular drug store.
Your mom has different symptoms so maybe she could get some help. I'm not sure if a podiastrist of a nonprofit hospital will be less concerned about overcharging patients than someone from a private clinic?
Did your mom try the over the counter stuff? You may also want to google to see if you could get more helpful info.
Good luck!