while i agree he should give a signed message and whoever dealing should either have him send first or maybe escrow...
your screenshot is meaningless
blockchain.info offsets after the 2nd decimal on btc amounts
edit: AND the qr code on the front screen when you login does not mean anything either...you can have 5000 addresses in a blockchain.info account that qr code is only to one of the addresses
well... I never seen this on blockchain...
And I checked source code of blockchain (css & styling) and I did not find it there...
and to QR code ... why would he delete his btc address than?
And no proof, that he has that money - just very suspicious printscreen (still edited)