If his H-4 visa in his passport does not expire yet, he may use the H4 visa to boad the airplane to US, and explain to the CBP officer at the port of entry that his I-485 was approved during his travel in China by showing the I-485 approval notice. Then, bring the green card to the CBP local Deferred Inspection Office to do the inspection again after entering US.
But if his H4 visa expired, he can not apply for the H4 visa and only the possibility is to get the Transportation Letter from a US Consulate in China.
