That’s the problem with a lot of dog owners my niece included. Especially if you have a big dog. They need to know how is the pack leader. And Tango obviously thinks he is. Once when we visited I had my daughter with me. Tango was body slamming my daughter out in the front yard. I got her and hi tailed it into the house. My nieces attitude was he was just playing. I said, no he was behaving aggressively. She didn’t believe me. The scary thing is, she has two small boys 8 and 5. I pray they are never hurt by that dog or the other one.
“Body slamming” *is* play behavior in all breeds.
However, your niece really should work on teaching the dog self restraint and what is and is not acceptable behavior.
While a *dog* would understand and appreciate that kind of play behavior, kids, not so much.
Dogs, being four-footed with a low center of gravity can easily accidentally knock down a two-footed high center of gravity person.
Your daughter was undoubtedly a novelty to the dog and he got overly excited by a ‘new thing’ in his world.
Odds are pretty good that he doesn’t act like that with her kids whom he sees all the time and is ‘used to’.
Any chance she would work the dog on-lead with your daughter or is she not particularly versed in dog training?