The USD isn't backed by oil, it's backed by full faith and credit of the government. A very small percentage of oil used in the USA comes from Saudi Arabia these days. https://www.eia.gov/energyexplained/oil-and-petroleum-products/imports-and-exports.php

Saudi Arabia depends heavily on the USA for defense and purchases billions of dollars of weapons a year.

Do some research on the stuff these people are telling you before you try to make financial decisions on it. I wouldn't take world advice or financial advice from these people, they seem to be in deep with conspiracy theories they see on social media.