suggestions needed to stop aggressive behavior towards a younger sibling

[Guest guest]

I need suggestions for advice/discipline for a friend from one of my

lists….she has a 4 ½ yr old son w/Ds who is having a lot of aggressive behaviors

towards his younger (2ish) brother…pushing, hitting, sitting on him,  etc…..(I

told her that  w/my older boys who are 23 and 21 yrs old now, I was amazed when

they were around the ages that her two are now…..that I had to TELL them

not to sit on each other… I mean,,,you would sure think that that would

be a ‘given’

 But anyway….any advice?

Thanks.

KathyR(mom to Danny, almost 8 and his 6 older sibs)