Any foreign SIM card can bypass GFW if you use data roaming. It's true that connect to VPN is banned in mainland China but don't worry, almost all corporate universities and research institutions have VPNs and no one will come after you. So connect your wife's laptop to her employers vpn network is ok but I think it will be slower than here. You can also buy other VPNs beforehand if you don't need to access to work related stuff.