I was reading Harry Potter I. I stumbled over a sentence, written there, whose overall meaning was clear to me but grammatical structure was not clear at all. Here is the sentence:
"Mr. Dursley was enraged to see that a couple of them weren’t young at all; why, that man had to be older than he was, and wearing an emerald-green cloak! The nerve of him!"
What kind of use is this "why"?
How does the present participial phrase "and wearing ... cloak!" fit in the sentence grammatically?
Thank you in advance.