I wouldn't give him zero percent odds, but there is no way I could recommend this approach in good conscience to someone without a PRC visa (or people with visas who aren't prepared to spend an extra month in HK)
1. Getting rejected for the visa application is a real possibility, no matter whether or not he meets the requirements because rules change all the time and there is a subjective element to the process that us mere mortals can't control
2. If he does manage to score a flight from HK to Xiamen or wherever, that flight might not actually happen, and Xiamen Airlines doesn't care enough to put him on its next flight (it could be three weeks later anyway)

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