He could be saying that low oil prices are not being caused by the Saudis, but by a global recession. The point is being made because no way increased supply can possibly cause such a huge drop. See http://davidstockmanscontracorner.com/occams-oil-razor-oil-is-falling-hard-because-world-demand-is-falling-hard/
In that case, interest rates will go down, though, yes, can’t go much lower.
Lower oil prices are being caused by two things: The first is a price war between Saudi Arabia and the United States. The Saudi's are desperately trying to undermine the Light Shale Oil revolution in the United States. The second is they're also trying to protect their own market share against other OPEC members giving "discounted" prices to the Chinese.
Now the side benefit for both Saudi Arabia and the United States in all this is the economic damage being done to Russia, Iran, Libya, and Venezuela. Russia and Iran are common enemies to both Saudi Arabia and the United States. So there's some "satisfaction" in hurting both of them. Libya and Venezuela (along with other OPEC and non-OPEC members) rely on high oil prices to support their economies and "social programs." Both countries are in economic collapse, which happens when you're one export is oil combined with a socialist/marxist government with central economic control.
The point is being made because no way increased supply can possibly cause such a huge drop.
Actually, yes it can. It's called OVER-SUPPLY. Three years ago the United States wasn't pumping millions of barrels of light shale oil daily. Today we exceed the output of Saudi Arabia, OPEC's biggest producer. We did that in three short years. Adding NINE MILLION new BARRELS OF OIL PER DAY absolutely will - and has - had a major impact on oil prices. The Saudi's themselves recognize the shale oil boom as the biggest threat to them.
Now are deteriorating economic conditions in China contributing to the collapse in the price of oil? Absolutely. How major of a factor is China's economic collapse vs. over-supply? I don't think we know that yet and your guess is as good as mine.
Can low oil prices spur economic recovery? Absolutely, see my post above how.
The increase in oil supply was not from the Saudis. They decreased their production in 2014.