Why dose my rottie not like my brother in law near my 5month old baby

My first rottie, Cleo, did the exact same thing to my grandmother and my daughter when she was a baby. She is now 19. But never was Cleo mean about it she just didn’t approve. Would block her from the playpen or reaching to pick my daughter u. We found out later that Grandma had Hepititis B and always wondered if Cleo knew it somehow.

Momma bear does they same thing with certain people she tries to protect the kids and I . I found out one person that walks by is a drug user, another is a ped, so I really think there is a reason the dog is trying to protect your child.

My Brooklyn girl did that with my grandbabies maternal grandmother. She always got between Kaidence and her grandma. Come to find out, she was a drug user and has been in prison for 8 yrs now. So trust you rottie, they are far smarter than you think. They will protect your baby with their lives.

I train dogs and I would say: trust your dog!
Your brother in-law may show Pedophile behaviour, be on illegal drugs, or just have a chemical imbalance ( an undiagnosed mental health disorder) or be on legal drugs. Your dog is showing protective behaviours over something, you may never know what but my advice is to talk to your brother in-law, is he using over the counter drugs? Could be as simple as that, but make sure he is as safe as your child, as in a altercation with your Rottie, I can guarantee he will come off second and worse case scenario your child will be hurt in the cross fire.
I have met dogs who can smell cancer before it is detected by ultra sound, I have worked with drug dogs and dogs who are sensitive to epileptic fits. Dogs see things us human need mechanical assistance to know, so be patient time may tell you why your dog don’t want hom around your child.

Good Luck

My 7 month old Rottie is displaying a vaguely similar behavior toward my 9 month old nephew. If he starts crying, she’ll get huffy with whoever is holding him. Doesn’t matter if it’s me, she gets very clearly pissed off about it. We assume she is just blaming us for him being audibly upset.

Here’s where it gets a little weirder: she doesn’t like much when my brother, his father, is holding him. But for this, I actually know why. When Izzy (my pup) was very small – about 11 weeks old – my brother completely lost his damn mind and shoved her, hard. He was sitting on the floor and she jumped at his face, trying to play with him (she was a baby, I’d had her all of a week at this point), and he overreacted and shoved her so hard he actually kind of launched her across the room. She was unharmed, but he scared her real bad. And she’s not crazy about him (which is huge, because this dog has never met a stranger in her young life). She watches him like a hawk when he has the baby, will follow him around if he’s walking, etc.

She doesn’t trust him, because he showed himself untrustworthy in her eyes. I would say that most of the advice so far is valid: If this is unusual, then your dog has a reason. It could be as simple as your brother-in-law not being particularly nice to your dog, and your dog deciding that means he is not a trustworthy person.