It will grow back slowly. Keep it well watered and fertilized and it should be OK.

Cutting away what was REALLY dead will not hurt at all, and, in fact, will help the tree recover more completely and quicker with less chance of disease entering through decay later on. If the limbs he removed were truely dead AND he prunned them in a proper way, he did you a favor. My guess is that if the limbs had still been alive they would have leafed out by now. The damage was done by the cold, not your dad.

After the cold snap, experts were advising not to prune immediately to avoid cutting off live areas that only looked dead and to reduce stress on the plant that often follows pruning and the resulting growth sprut. But, waiting a year will not make dead limbs come back to life.

P.S. ... DON'T fertilize your tree unless you do a soil test and the test shows that your soil needs fertilizer. Fertilizing trees without testing first is generally not a good idea and is more likely to hurt, than to help them unless the soil lacks necessary nutrients. Trees have very different nutrient requirements than flowers or vegetables. Most soils have the nutrients (mainly nitrogen) that trees need without adding additional fertilization.

Also, only water the tree when needed. In this drought that may be once or twice a week, but the tree will not need any more water than it would have if it hadn't been hurt by the cold. In fact, it should need less water because there will be a greatly reduced leaf surface with original root mass. Basically, water when the soil becomes dry at a depth of about 2 to 3 inches. Fertilizing or overwatering will cause additional stress on the tree and could easily result in a longer recovery time or even death.

If it were my tree, I would make sure the pruning was done correctly, ensure that the area around the tree was free from weeds and mulched lightly, and water the tree only when conditions (drought) make watering necessary.