If you are living in San Antonio there is a good pediatric cardiologist named John Brownlee. He is not a fetal cardiologist, but he may be able to head you in that direction.
Without evaluating your baby, I cannot say what can specifically be done for him. For our other readers, complete heart block is the inability of the electrical signal to get from the natural pacemaker of the heart in the upper chambers (atria) down to the bottom chambers (ventricles). This causes the heart to go much slower than usual. I can say that if there is hydrocephalus and he is already showing evidence of growth retardation, his prognosis is probably not good. However, it would be important for you to be evaluated by a pediatric cardiologist who specializes in fetal cardiology. There are both university as well as private practice pediatric cardiology groups in San Antonio who could see you. Most of his prognosis depends on his heart rate at this time. If his heart is not able to meet his body's needs, he will develop what is called hydrops, which is a version of heart failure. If his heart rate is fast enough or his heart is able to pump enough blood out, he may be able to grow and get near term. The other concern is, in the face of heart block, hydrocephalus, and intrauterine growth retardation, whether there is an associated genetic syndrome causing this.