The word "him" here refers to Cornelius. Here the words "You" and "you" are plural and include Cornelius as well as the Gentiles who were present. (See: [[rc://en/ta/man/translate/figs-you]])
"many Gentile people gathered together." It is implied that these people Cornelius had invited were Gentiles. (See: [[rc://en/ta/man/translate/figs-explicit]])