Would you tell your brother his girlfriend is cosplaying as a Mexican womam

I found out my brother's girlfriend has lied to him about her whole life. We are half Puerto Rican. He met a girl who said she was Mexican. She looks very white but there are white latinas so I didn't question it. She knew Spanish but her Spanish was little... Choppy. She told my brother that her parents are in Mexico and they sent her here when she was 18 for a better life. Her last name is also Lopez. Well. I have a coworker. I was texting my brother on messenger and his picture has his girlfriend in it. My coworker saw and said she went to school with her. I said she didn't come to America until she was 18. My coworker gave me a look and said "She's from Minnesota. We went to school together. I'm not gonna lie. I'm bipolar and was going through mania. So I was manic which is why later I ended up going on a deep dive and finding out EVERYTHING about her. 1. She is 100% not Mexican. She was married to a Mexican man. I found their marriage license and divorce certificate once I figured out her maiden name. Her actual last name is Jefferson. Can't get more white than that. She married a man with the last name Lopez and then they divorced and she kept the name. I also ended up finding her entire family. Her parents don't live in Mexico. They live in Minnesota. I went through her mom's Facebook and the girls OLD Facebook and I don't think she's even been to Mexico. She's cosplaying as a Mexican woman. I don't know why and I feel like I should tell my brother that she's lied to him about everything.