Single parents' rights

My brother and his girlfriend have recently split up. They have a 2 year old daughter together.
It was the girlfriend's decision to split and despite my brother being completely gutted, he left the family home in order to "not upset the daughter" (this excuse has been used by the girlfriend to pretty much get what she wants). He hadn't cheated, hit her etc etc, it just came out of the blue to all of us.
He's been paying maintenance (which she hasn't declared) and has had amicable access several times a week. Now she's suddenly decided that he can't see his daughter at all (coincidently this coincides with him having a date with another woman).

As an unmarried father what rights does he have? He's also on a relatively low way and there's no way he could afford a lawyer if that would be required.

ooooo don't tempt me!!!

Oh he's had all the lectures, great coming from your little sister!!