A contractor looked at our house and told me that you can't fix a house (with old wiring) that has some outlets that are not grounded. He said that you can go on YouTube and search the internet and it will tell you that you can. He says that the only way to properly fix and ground everything is to do a whole house rewire.
Is he correct?
If, theoretically, you have an old house that has no ground whatsoever, can you run a grounding wire from the panel to all of the outlets to fix this?
We have BX/AC wiring. And also apparently we have "...old-style AC (BX) with cloth insulated wires in a paper overall wrap under the spiral armor (no bonding tape)" Courtesy of @ThreePhaseEel.