Argentina rental properties

[Courtney Van Ek]

Hi everyone, new to the forum- been in real estate over 10 years and running upon foreign territory (literally). My boyfriend inherited 5 rental properties with no mortgages in Argentina after his father passed away. They are all supposedly occupied and his aunt has been collecting the rental payments on his behalf the last 5 years. He is ready to sell them but his aunt doesn’t want to give up her monthly cash flow even though they are legally his. How would one go about proving the ownership in Argentina and listing/selling as a non-citizen. He would need all of the rental information, payment history, etc but it seems the aunt has no lease agreements in place and everything is done in cash (this part of Argentina is very poor). Anyone dealt with this situation before or would advise a reputable person to speak with on where to start? Thank you!