My boyfriend made friends with this girl online

My boyfriend has autism and isn't good at making friends. I go out with my friends every week ad he stays at home watching tv. He tries to make friends bug people think he's weird. I told him to just be confident and straight forward... So he started sending friend request to people in his "You may know" on Facebook and sending the text "Hi. I'm Kingston! Want to be friends?" I guess q girl said yes and he got happy and he has been texting her. She seems to also be flirting but flirting goes over my boyfriends head. He had no idea I was flirting with him before we dated. She invited him to come hang out with her and some friends this weekend. He said ok and told me.... He's hanging out with someone he barely knows... A girl. More like women. She's 32 and we are both 18.. How would you feel?

Edit: My friends think he's weird. He gets too loud and hyper and when I hang out with my friends I want it to be chill.