Best bet-see a guardianship attorney to determine if you can start a procedure to be appointed as guardian.
The answer given does not imply that an attorney-client relationship has been established and your best course of action is to have legal representation in this matter.
If your aunt is incompetent, she can not give anyone a power of attorney. In Louisiana you will need to start a court proceeding called an Interdiction. You will need to prove she is unable to care for her self or her affairs. You need to engage the services of a Louisiana licensed attorney familiar with interdiction proceedings.