Genuine professionals who know how to enable an abused child to recover and come to terms with what has happened to them would never dream of setting themselves up as experts, and parents are given the support they need to enable them to be helpful to the child, too. Ths mum may need some help to do that, as she is breaking down due to the shock of this incident, and at the moment might not be the best person for her child to talk to about it. The child doesn't need the burden of watching her mum falling to pieces, but mum will be able to tell her how sad and upset she was at a more approprite time.
Anger management!!! Help needed.