Yes, you can deduct the interest that you pay because you own the property, even if you are not on the mortgage.
Regulation §1.163-1(b):
Interest paid by the taxpayer on a mortgage upon real estate
of which he is the legal or equitable owner, even though the taxpayer is not
directly liable upon the bond or note secured by such mortgage, may be deducted
as interest on his indebtedness.
https://www.law.cornell.edu/cfr/text/26/1.163-1
