Carl's comment is the correct answer; you can claim it if you paid it and you are on either the mortgage or the deed.
A bigger question is can the other person claim Head of Household if they are not paying the mortgage.
The main requirements for Head of Household are: a taxpayer that
1) is single or did not live with their spouse at any time during the last
half of the tax year.
2) has at least one closely related dependent (usually a child) that lived
with the taxpayer for more than half the year
3) pays over half of the support of the household expenses, including rent
/ mortgage...
