From my brief research, there *is* CDMA in some major Chinese cities, but note that you WILL be roaming, so you will be charged a bunch for any data/calls you make. It'd be cheaper to buy a prepaid phone in China, if possible.
Rooting the phone makes no difference.
Most Verizon phones, unless it is a 'Global' phone do not have SIM cards and do not work in GSM networks, which is what the majority of the rest of the world has. Verizon (and Sprint as well) run on CDMA networks, where the SIM card is, in a simple way, embedded into the phone.
If there's a carrier in China that he can sign a contract to, he should be able to activate the Incredible with them, but he would have to pay the ETF with Verizon.