Very true, but not submitting a completed Profile should not have any impact on the release of an offer of admission.
I think that encouraging OP to go snooping around in her mother’s tax and financial information is a terrible idea. OP’s mother is perfectly within her rights to maintain her financial privacy, both in relation to college financial aid offices and her daughter. Any strain that exists now in the mother-daughter relationship will only get worse if and when mother finds out her daughter has violated her privacy and shared that information with others.
The best thing that OP can do is talk to a trusted adult (the suggested GC, for example) and ask for some help in communicating with mother and explaining how need-based financial aid works and what’s at stake.