You can apply for a visitor visa -multiple entry within one year, normally it will be good for 6 months and you will need to travel back to China and come back again for another 6 months.
That's all I know.
By the way, I have a friend had a baby in the U.S. as well. Can you help me to find out how your friend's son can remain U.S. Citizenship? The parents are Chinese and the baby is American, however Chinese do not recognize the baby as American. How can the baby remain in China while keep the status of American Citizen.
If yo can let me have some input, it would be greatly appreciate it.