I'm not an economist (though I sometimes have to listen to them) and the logic is that inflation increases the value of assets (e.g. houses) with regards to other things (e.g. wages), so the well-off benefit from it.
Tariffs wouldn't ordinarily help the very rich as they tend to get rich from free trade and helps ordinary people more. E.g, you make cars - you get your steel from abroad because it's cheaper - and the local steelworks becomes uneconomic and closes.
Apparently an article in today's Times suggests the logic in the Trump tariffs is to rebalance US trade, hence the countries with the biggest surpluses have been gone after. I haven't read the article. But it doesn't make economic sense: running a deficit with a country might make the best sense, depending on what they're selling.
The other possibility is that Trump and his friends placed bets on the market, knowing what was coming but, tbh, I think they just like playing God. They'll always have a roof over their heads, unlike the little people.