Maybe, since she lived with both parents over half the year, it would come down to who paid the cost of maintaining the home.
Head of Household
You may be able to
file as head of household if you meet all the following requirements.
- You are unmarried or considered
unmarried on the last day of the year. See Marital Status , earlier,
and Considered Unmarried , later.
- You paid more than half the cost of keeping up a home
for the year.
-
A qualifying person lived with you in the
home for more than half the year (except for temporary absences, such as
school). However, if the qualifying person is your dependent parent, he or
she doesn't have to live with you. See Special
rule for parent , later,
under Qualifying Person.
Qualifying Person
See
Table
4 to see who is a qualifying person. Any person not described in Table
4 isn't a qualifying person
From <https://www.irs.gov/publications/p501#en_US_2017_publink1000220814>
Costs you
include.
Include
in the cost of keeping up a home expenses such as rent, mortgage interest, real
estate taxes, insurance on the home, repairs, utilities, and food eaten in the
home.
Costs you don't
include.
Don't
include the cost of clothing, education, medical treatment, vacations, life
insurance, or transportation. Also, don't include the rental value of a home
you own or the value of your services or those of a member of your household.
