To save time, he sent the tapes to a professional.
I don't understand why you wouldn't record the audio and video stream differently - with an SVHS player, you could output s-video and capture that at better quality and then audio separately from the RCA lines. And then use virtualdubmod to time it properly, then curate.
But then again, if it randomly got out of sync in recording, that could be annoying so maybe I don't fully understand the issue.