I had a conversation with my DDs about this age, about the nature of social interactions. Basically 'just because mummy talks to someone it doesn't make them my friend. There are people I talk to (in the street, at a cafe) who are really strangers. Friends of friends at other people's houses are also really strangers to me. Don't count them as trusted adults.'
It was a light conversation, but repeated every time they referred to someone as a friend, or asked who they were after we'd chatted.
It might be a stepping stone to a conversation about trusting 'closer' friends and family. We did go on to have that conversation, when one of my DDs noted that the small 'trusted circle' was all women (except for my DF) and never included their partners. I explained that Laura was my friend I had built a relationship with, and her husband Dave (obviously name changed) had been a friend for a long time, but I don't know him as well as Laura.
Laura can pick my DDs up from school anytime. Dave would need a phone call to the school to authorise (which he has in an emergency, bless him) or to use the password to confirm I'd sent him.
I agree that he's pushing your boundaries, and this is never a good thing. It's either a lack of respect for you, for women setting boundaries, or many other things, which lead up to grooming and him being a predator. It doesn't matter - pushing an adults reasonable boundaries is ALWAYS a bad thing.
Call him out in front of people, every time. Be utterly reasonable to start with. Say that you've told him it makes you uncomfortable, and you don't let just anyone do this - as you teach your DC how to set personal boundaries. Put her down now. Please.
After a couple of times of this, start to ask why he is disregarding your feelings and wishes. Insist on an answer, and no deflection from him back at you being unreasonable. Reflect that back to him as not answering, and insist on an answer.