My brother asked this question earlier this week and at his suggestion, I’m sharing the answer here.
He mentioned that he thought the search in Gmail wasn’t very good (which is preposterous since it has no match). He went on to explain that his searches weren’t finding items he had deleted. “au contraire”, I quickly retorted. I told him Google’s Gmail does search his Trash, but, he, the user, needs to click a small link at the bottom of the search results in order to display those extra results.
After he tried it with a few searches, he was quite pleased and said he never remembered seeing that link.
Here’s a short video explaining how to get Gmail to display those search results from your trash.