First off, I wouldn't have made it so the guy had to come to me. Google or not. No reason whatsoever he'd have to know who I am or where I live.
I'd have looked for a business card in the wallet, and called the office phone first, to make sure it was really a legitimate number. Then I'd take the wallet to the office building, telling the receptionist it was a "personal matter". If that got me into his office, face-to-face, I'd make sure he looked like his driver's license picture.
I'd probably shoot the shit with him a while. Ask why a guy like him is using the subway in the first place, then how the hell could he lose his wallet like that? I'd hope to get a Diet Coke while we talked (or a scotch on the rocks, like you see in movies

)
After that, I'd have accepted cab fare, parking fees, or gas mileage. Typical travel business reimbursements, but nothing more.