I just read what happened... Rojas is the son of Felipe Alou but it's actually Rojas who has the correct last name!
Due to a paperwork mistake from a minor league employee when Felipe came from the Dominican Republic in the 1950s, Felipe's last name was written as Alou, his mother's last name, instead of Rojas which is his father's last name. So Felipe Alou's name is actually Felipe Rojas but he just kept the Alou name in the majors and never bothered to correct it. When his sons got to the majors they kept the incorrect last name just to be consistent with their dad. So basically Moises Alou is actually named Moises Rojas.