I have 5 children,2 of our children are autistic and our youngest daughter who is autistic is also physically disabled.
Of course siblings will argue and sometimes they can fight as well.It's because they spend so much time together under one roof they're bound to rub each other up the wrong way now and again,just like adult couples can.
I step in if I need to,they're not allowed to disrespect one another by calling each other names or saying something horrible to one another.Of course they do now and again but then we deal with it straight away.
There could be some pushing or hitting when they were younger,I'd always step in and stop it and they'd get into trouble for it,but now they're older that never happens.
They're all very protective of they're brother and sister that are disabled and extremely patient(they have more patience with them than a lot of parents do with they're own children)and they'd never say anything bad to them or push or hit them even when they were all very young.
I can see a problem when it's brewing now between the children so if someone's in a grumpy mood and likely to snap at the others I suggest they go and have some chill out time on they're own it always works.
I have to say though we've been really lucky with our children,they're all really close and very protective of one another(God help anyone that try's to pick on one of them)and they really like each other.
I have friends who's children try to tear lumps out of one another (which I find really distressing)and whom seem to really hate they're siblings.I know my children all really love one another and they all say that they're brother's and sisters are amongst they're best friends.