Intrusive or sensible? Not sure what to make of this

[MeadowGlass]

I am close to my nephew. He is 16 years old and has always known me as his aunty. I am married to his dad's brother. He sees his dad on weekends as his parents have been divorced since he was 6.
My nephew has been in a stable relationship for a year. I know his girlfriend, they're a lovely couple. I know they're intimate but I've never found it my place to enquire anything about it, in terms of safety, etc.
Nephew is angry and upset now. His dad took it upon himself to ring girlfriend's mum and discuss their intimate relationship and say that they should be careful. His dad is a forceful man (a bully to be honest), and he probably took the stance of self righteousness. Nephew had no idea he was going to do this.
I only have a young DD so have years before I get to the teenage years, but is this a normal thing to do nowadays? Nephew doesn't want to even see his father now.

That is not normal.
Normal would be discussing safe sex and contraception with his DS.
The GF’s parents would have (hopefully) had the same discussion with their DD.

No it's not normal. He has made an arse of himself and embarrassed his son and his girlfriend. The responsible thing to do would be to speak to his son and keep him supplied with condoms. Is he a bit misogynistic? I'm wondering if he meant it as a "make sure your dd doesn't trap my ds by getting herself pregnant".

@Blinkinbloodyhayfever, he's incredibly misogynistic and I suspect that might have been his angle, the whole not trapping his son narrative.