there is a concept called equitable ownership. if you are an equitable owner you can deduct mortgage interest and maybe even the real estate taxes if you pay them even though you are not the owner of the property and are not on the mortgage. with what little you provided I would say you aren't an equitable owner. However, there may be important information you omitted. The question of EO is often decided by the Tax Courts based on all the facts. if you think you are an EO, consult a lawyer who can look at your situation as it compares to Tax Court decisions.
as an example - in Phan, TC Summ. Op. 2015-1 the taxpayer provided clear and convincing evidence that he was the EO because he paid the mortgage, taxes, insurance, other bills associated with the property, maintained the property, and made improvements.
