Learn English – a bromide

No, the line didn't say that 'people were concerned about (for) money'. It said that the solutions advanced to solve people's unhappiness concerned money. In other words, the author is making the comment that the suggestions did not address people directly, but were centred on money, as though money, if properly manipulated, would make people happy.

So, it's the people who're unhappy, but it's money that's receiving the attention, even though money isn't the unhappy party.

So, perhaps the suggestions the author is talking about run along the lines of buying stuff, or becoming more financially secure, etc. Financial gain is being addressed, but not the roots of people's unhappiness.

It's in two parts.

"Good afternoon," said the stranger

and:

regarding him, as Mr. Henfrey says, with a vivid sense of the dark spectacles, "like a lobster."

Lobsters have eyes that stick out, and he was regarding him 'like a lobster', which is basically 'very intently'.

The reason its in speech marks is because it is an expression of Mr. Henfrey.