To be honest your bhai approach sounds kinda lame. Family friends are family friends and unless you’ve been neighbours all your life and went to the same school etc. I don’t see how a girl coming to see a family friend’s son as a bhai is possible. And that the brotherly feeling is SO strong that she absolutely can’t marry. I don’t see that working, I’d think the other family would politely back off but they would still know you’re bull****ting them.