You can't claim property taxes unless you are
- Legally obligated to pay them, and
- Actually pay them
However, if you can prove Equitable Ownership (EO) in the property, you may be able to claim them. But Equitable Ownership is not necessarily what one may think it is. See IRS Court Ruling 2001-0072 at https://www.irs.gov/pub/irs-wd/01-0072.pdf for the specifics that I am aware of. (There may be other things that I am not aware of or privy to.)
