Once again, FAFSA doesn’t give you money. It’s just a form. The most aid you can get from the gov is a few grand less than 10k (which would be the full Pell). If he got that much, it came from either the state or the school (in addition to the feds if he qualified for Pell).
What is your EFC currently without the money?
Did you have to enter information about your income and assets? If your parents made less than 24k and could answer yes to at least one of a series of questions OR if they made less than 50k and could answer yes to a question, then they qualify for auto-0 or simplified needs (respectively). Both of these disregard your assets.
Finally- IF your brother made a mistake in not including it, that doesn’t mean that it’s OK and you can do it, too.