| Quote #1
He had to go very close to see that it was an old man, a very old man, lying face down in the mud, who, in spite of his tremendous efforts, couldn't get up, impeded by his enormous wings. (1)
And here's proof that age isn't just a number: the first thing we notice about the angel character isn't that he's got wings; it's that he's a very old man. In other words, his old age is more important than his wings.
| Quote #2
There were only a few faded hairs left on his bald skull and very few teeth in his mouth, and his pitiful condition of a drenched great-grandfather had taken away any sense of grandeur he might have had. (2)
The narrator lays it right out for us: old age is not pretty, it's not sexy, and it's definitely not very angelic. In fact, it's downright ugly and mortal. (In the worst sense. The sense where you die.)
| Quote #3
"He's an angel," she told them. "He must have been coming for the child, but the poor fellow is so old that the rain knocked him down." (3)
Even if the old man is an angel, he's a victim of old age just like any regular human: he gets weak, and isn't able to do his job or drive in the rain. And what do we do with people like that? Well, we don't stick them in chicken coops—yeah, you can take a minute to pat yourselves on the back—but we do like to stick them in nursing homes.