Sentence:  [H]e smiled ... then asked my name. He checked it against his clipboard then sadly shook his head as if he'd been rejected himself. Told him I was looking for employment and he <WSD>happied</WSD> up again, able to help by directing me to apply at the front office, that the doors were on the Gower Street side. 
Meaning of the word marked with <WSD> tags:  "Often followed by" '''(up)''': to become happy; to brighten up, to cheer up.