Joint Rental with Father !! How to split income.

[John Ba]

I bought a investment property in a foreign country many years ago. The property was vacant for at least 20 years , and we kept on paying 100$ a month for maintenance. I paid 100% of the cost for the property , but while getting the deed( Tenancy in Common is default  in the foreign country) added my dads name to for convenience, as he being retired had more time to travel and do any tasks. Now he is 85 and in declining health and cannot travel anymore. I rented the property in 2022 and my dad signed a paper confirming that he relinquishes his right to the property as well as that he did not pay any capital .  This relinquishment/statement was not recorded in the foreign country court. I don't have any bank records from 20 years ago to prove anything. Can i take all the income / deductions / as well depreciation on my return ? Or we have to do 50%-50% ?