The Childrens Act defines Parental Responsibility as “all the rights, duties, powers & responsibilities which by law a parent of a child has”. A Mother has PR by right a Father does if he was married to the Mother at birth or if the child was born after 01-12-2003 and his name was on the birth certificate as Father, he can make an agreement with the Mother or apply to the Court for PR.
Your Brother may also wish to consider obtaining a Contact Order. As stated by others many people successfully represent themselves in the Family court and many more probably will in the future with the restrictions in legal aid.