For $65 you should have gotten air mail through the USPS. There is no tracking number for this kind of thing, but he'd have to fill out the large, white customs form for stuff over 3lbs. I'd also think that he'd insure a $400 package.
Air mail to Taiwan takes about 10 days. Surface mail is advertised to take up to 6 weeks, but it's always been 2-4 weeks for stuff that I've sent. In either case, there's a customs form that's stamped with date seals by the USPS. Ask him to see a copy of the customs form or the receipt (which has the destination and date on it).
Good luck... and why didn't you just buy one in Japan.