If you have been appointed executrix dative then your brother is irrelevant in this box.
You should say, "that I am executrix dative qua daughter of the said (deceased) who died on (date) conform to decree of this court dated (date of decree)."
I hope that helps. Please leave a positive rating so that I am credited for my time.
I don't usually do that but you can put in "and I am entitled, along with a brother of the full blood, (name), to share the intestate estate of the said deceased."
The reason I don't put that in is that it should already been said in the application for your appointment as executrix dative but there's no harm in putting it in if you want to.