Your brother is in very good company, and watching market sentiment can tell us a lot even while it tries to make people buy high and sell low. Some people just say the market's rigged and it's sinister forces that are sticking to the little guy. My take is that it's the human emotions that are what's messing up market prices and that the more sophisticated we get then the more we can overcome fear and greed and do what works.
(Wyatt, a while back you posted a terrific graphic on market sentiment on surges and dips and how natural human emotions were so counterproductive --if you remember where it was please repost.)
IMO, market sentiment is one of the best historical technical indicators there is.
Emotion is the key driver. I’ve seen people walk away from once in a lifetime deals because somebody hurt their feelings. The efficient market hypothesis doesn’t fail because people are emotional. It’s part of the deal and smart investors watch sentiment. The more people hate a sector or investment the more reasons I like to look at it.
I love buying out of favor bargains, particularly when the “smart” money rejects it. That’s why rental housing has me nervous. Too many “smart” guys in it right now. There’ll be a washout one way or the other.