I am just here wondering how rich OP is considering he is thinking about buying real estate properties in different countries. Usually people tend to just buy real estate properties in their own country. Probably for easier maintenance and surveillance.
It also helps that you are most likely to be aware and understand of the laws and everything legal matters in your own country where you are a citizen of. I am sure there are some peculiarities when you buy assets in a country you are not a citizen of and that sounds like extra work.
Perhaps he has all the financial resources to make it happen but like you said those kind of investment is mostly important doing it at your place of residents because challenges can arise in the future were the person may not fit in the necessary criteria to own an estate in another country because as time is going that's possibly how some country policy is also changing and the best suitable way is actually if the person is a resident to that country, however I would have suggest having a company on those countries instead but it still fall under the chances of real estate, so actually I think is best to diversify those money on his country instead to avoid traveling all the time because of emergencies or other matters.