I jsut got the most disturbing news

So my SIL has been wanting to talk to me so she came over with her husband to hang out tonight. The brother's went to buy McDonald's for the kids so we took the opportunity to talk. SOOO my "fiance" went on a 3 day trip to his county with his father for some business. When he got back he told me he finally met his older sister which i was happy because i always heard about her but no one had ever met her aside from my father in law. Now its been 2 years since this trip and my SIL is telling me that my fiance grandmother called my brother in law to let him know the marriage paper work was coming through. I'm confused when my SIL is telling me, then she goes "oh you didn't know," I'm there like 🧐🤔 know what? "They went to DR so your fiance could marry his sister in exchange for the properties in their country, he would bring her to the US to have a better life"

🤢🤢🤢 WTF so i go on investigation mood, i wasn't able to find anything online or even on his phone aside from regular conversations in between a brother and sister but I'm not completely sure so i obviously what to talk to him but how do you even ask a question that disturbing. I want to say he would never do that cause i can't see it, it isn't of his nature to be like that but you don't ever fully know anyone. Specially when money is involved. I've been when this man 7+ years we got together every young, i know his whole family and vise versus, we have 3 beautiful kids together. I'm confused ladies please any advice? If its a negative comment keep it to yourself i have enough going on and just need an outsides option on how to even go about this situation. I am going to the marriage office tomorrow but I'm not completely sure how much that would help being that he would have gotten married in another country.