My DB and I have kids almost the same age. His is, imo, a normally-behaved 5yo, like mine (ie pretty good most of the time, polite, has his moments like any other kid) - but DB seems to think he's really not.
Background is that I've come to recognise, partly through MN, that our dad could probably have been classed as abusive - frequent shouting, sulking, constantly on at our mum, unreasonable demands on us all, demanded respect but never gave it etc. His way of discipline was just shouting and punishment. My DH is calmness personified and showed me that this wasn't normal and we deal with our DC largely without it (which takes a lot of effort on my part but seems to work mostly).
DB is turning into my dad. He split from his DC's mum but she was like that too - both very short tempers and imo unrealistic expectations of the child (eg she would shout at him for not looking at her when she was talking to the DC when he was 10mo). Nephew is constantly in trouble - slightest thing and he's sent to the naughty step / punished in some way. His SB and DSis seem to be treated a bit differently, not as harshly, and I can't help feeling sorry for him! DB has very fixed ideas (eg he gives him loads of dinner and won't let him leave the table til he's eaten all of it when the poor kid can't manage any more, but won't let him have more breakfast when he's still hungry).
DB says his behaviour is challenging, which may well be the case when we're not there. They suspect he has ASC so I did give them some tips on it as I have it myself and have also worked a lot with kids with it - but stuff like naughty step just doesn't work with autistic kids and all the stuff he is doing is, in my view, just likely to make jt worse. He doesn't recognise that our DF was abusive and I know DF made me worse because of my autism, and I desperately don't want this for my nephew too. He's not a bad kid - I think DB sees our DC and thinks they're so much easier, but they're not, we just deal with stuff in a calmer way (which DH does brilliantly and I do my best at and sometimes fail!).
I can't do anything about this, can I? I know it's not my business but I can't help wanting to scream 'Don't be like our dad, it's not normal!' :(