try and look at it as "all behaviour is communication"
he cant communicate properly (eg say "let me go first!") so he uses physical methods. try and see what his beahviour was trying to say - eg let me go first ! my turn! etc
showing him that roaring and shouting works really isnt the best way forward.
try and arrange some turn taking games with him and your dd at home. teach him (show his mum how to teach him) turn taking etc.
behavioural input can help espec if maybe ASD.
call NAS helpline see what local services there might be that mum could access. even if not diagnosed there may be support/local groups.
ask her what SENCO at school is saying. find out info on local educational psychology services encourage her to self refer if school isnt acting.
you asked earlier:
"How do you teach a child this?"
well with specialist behavioural support and intervention. but tehre are some ways you/his parents can do this - by teaching him appropriate behviour in games and play - an example being turn taking.
by analysing the behaviours when they do happen and trying to s ee what he was really trying to communicate then thinking ways to teach him appropriate behaviour in such situations a non-shouty non confrontational way. role playing out the scenario with toys but showing the right way to ask or show the consequences - eg teddy pushes barbie over barbie cries sad barbie.
oh dear. now lets do it again. teddy doesnt push barbie is happy teddy is happy...mummy is happy all are happy etc
recognising he may need extra help and his parents may need extra support and helping them to access that