This is why it pays to be paid in advance - excuse the pun If she had paid in advance for the days booked and did not use them for whatever reason - too bad she had committed to them.

My contracts state:

Fees are due regardless of absenteeism / illness, inclement weather / acts of Nature beyond our control, when program is closed for public holidays or child is absent due to family vacation time. Unfortunately, part time families cannot make up absent days on another day. Fees are to be paid in advance of care in the amount according to your payment schedule.
And under preventing illness ...

Children may not participate, and will be required to be temporarily removed, if any of the following diseases and/or symptoms develop:
  • Vomiting**
  • Diarrhea**
  • Fever over 101 F
  • Unexplained rash specially accompanied by fever.
  • Suspected communicable disease until seen by a Dr. and confirmed that further exclusion is not required.
so the fact that she choose NOT to have his illness confirmed by the Dr in order to return 'earlier' is HER CHOICE ... she does not get to than turn around and say 'well you made him stay home so I am not paying'.