TLDR: yes, although your ideas about protection seem to me to be in serious need of cold showers. In my country the behavior you describe is both illegal and likely to end up with the threatening person in the nearest body of water to cool off (this is considered a milder alternative to calling the cops). Mind you, both of my bros have been date-smart, so they haven’t needed much “protection” on that subject; the youngest one has occasionally asked for advice. The one sexual predator from which I did protect them to the best of my ability was our maternal grandfather.
Long version: I’m protective of my younger brothers anywhere. Or of my work juniors (ask my PhD advisor what happened to his career after I found out he was out to scam all of us - it’s a pity we didn’t catch that valkyrie dive on video, cos damn it was beautiful). Or of my students (who have been about 70% guys, and until I “folded 45” were more likely to be older than younger). In Spanish it’s called “older sibling syndrome” or “shepherd dog syndrome”: we grew up watching and protecting herds of kids who may or may not have been biologically related to us, so we’re like Wonder Woman with more cloth. Or if guys, Spiderman minus the webs.
When Middlebro tries to protect me* and I get really, really, really tired of it, I ask him “exfuckingcuse me, WHO is Eldest? By six years? You may be taller now but you’re still my little brother, mister! Now go protect your children and leave my protection to me!” Littlebro doesn’t do no protectin’, he happened to be one of the youngest kids in any herd he was a part of. It’s one of the things Littlebro’s wife likes about him: she’s a much-younger sister and was born sickly, so her childhood was spent wishing she wasn’t as carefully bubble-wrapped as she was. A husband who assists but does not try to protect suits her just fine.
- Usually either him or his wife are missing important information or mistaking me for her little brother, whose financial status and decisions prior to meeting his wife weren’t even on the same planet as mine.