Responses

If they have follow up questions either say you don't know details other than that he's taken or just answer stuff about yourself idk, it's really not hard to lie about shit like that, they're just an acquaintance and will literally not need to meet the "gf", as far as they're concerned they just need to know he's taken and the rest is none of their business
I’ll forever not understand not saying yes when someone asks if your bf has a “gf”, bro who cares if you’re not a girl, for all purposes an outsider asks the answer is they’re taken and if you can’t say he has a bf then you should say he has a gf so they don’t decide he’s single and go on setting him up etc or have hopes of being with himmmm JUST SAY HE HAS A GF BRUHHHHH