If you are a U.S. citizen or resident you can only file as married filing jointly or married filing separately. You can file joint return as residents even when your spouse has never been to the U.S. On joint return you can claim your son. On the joint return, both of you must report worldwide income.

NOT quite true.

He can only claim the child if the child is a U.S. citizen and the child spent NO time in the U.S. in 2010.

If the child is a citizen of the Dominican Republic, he can claim him ONLY IF the child has spent at least SOME time in the U.S. in 2010.