In Reply To :
Access of bank accounts, financial statements
the given facts indicate that :-
1. Your parents are alive.
2. they do not know anything about banking.
3. They are trusting your bother (not you) for banking matters.
4. Your brother is exercising his discretion withing delegation and giving you only that information which he feels is necessary.
You have no right on earth to compel your brother to share information about banking matters of your parents 9who preferred trusting him not you) .
Of your parents do no want any transparency towards you you have no remedy.