Rountrip ticket to Beijing from the States, but within 72 hours have a ticket to the Philippines...

Hello! My brother and his girlfriend want to visit me and travel in Asia. I heard about the 72 hour transit and was wondering if they got a roundtrip ticket from the States to Beijing, and within 72 hours they leave on a roundtrip flight to Manila and leave for the States again from Beijing within 72 hours.

So in short: Chicago-Beijing-Manila-Beijing-Chicago

Sounds crazy but I read the restrictions, and as I far as I could tell this would be allowed. Please help!