Can a secondary POA revert back to the original POA?

My Mom made me POA in 2000. In 2011 for convenience she made a neighbor POA. She recently had a stroke and became mentally incapacitated. The neighbor now has relinquished power of attorney. In this case will it revert back to the original power of attorney? Do I need a new p o a drafted? If so how do I go about this since she is mentally incapacitated? Would like to have a say so in her care as long as possible. Don't want the state taking everything and not looking after her well-being.