How is Boo Radley described at the end of the story?

From the text:

“I never heard tell that it’s against the law for a citizen to do his utmost to prevent a crime from being committed, which is exactly what he did, but maybe you’ll say it’s my duty to tell the town all about it and not hush it up. Know what’d happen then? All the ladies in Maycomb includin‘ my wife’d be knocking on his door bringing angel food cakes. To my way of thinkin’, Mr. Finch, taking the one man who’s done you and this town a great service an‘ draggin’ him with his shy ways into the limelight—to me, that’s a sin. It’s a sin and I’m not about to have it on my head. If it was any other man, it’d be different. But not this man, Mr. Finch.”