degrease the area and lightly hose it off. The pump/steerign gear box, and anywhere the lines run. Air bubbles indicate a leak from somewhere, so you should see it on clean surfaces. It could be a loose hose, missing o-ring on a line, etc. If you cannot repair it yourself, I'd go somewhere else. If he isn't warranting his work (free) -he is either using bad parts or isn't very good at his job.
Power steering pumps require bleeding before you start the engine (same with replacing the steering box). If that pump runs dry for just a bit, it'll get ruined.