China domestic, as most of the world outside North America, operates by weight not pieces. Your husband should seriously consider getting the PVG-Fuzhou flight changed to first class. The fare is RMB 1170, or only RMB 390 (US $57) difference over full fare economy. In first class, he'd likely get away with no excess baggage charges (do have him try to lighten the load to 44-45 lbs per bag though). And of course, a better seat and maybe better treatment and lounge privileges.

With all that weight in Y class, the likely excess charges will gobble up nearly as much as the differential for first class ticket. Of course, your differential will be more if he's on a discounted economy ticket fare. Or, since he's travelling for business presentations with materials and works for a company, he should get straight with them that they will be reimbursing any excess baggage fees.

On check-in, most domestic flights open up for check in a couple of hours ahead of departure. Unlikely that he can recheck them with Xiamen 7 hours early, but worth a try. If they refuse to take, he can find Left Luggage counter and park them there, for a fee of course.