It's difficult to say whether this tree will survive. There is quite a lot of damage. The presence of ants usually indicates an abundance of aphids. Aphids are a sucking type of insect that are able to penetrate into the tree to obtain their food. They produce a nectar which is desirable to ants. The ants in turn tend to cultivate the aphids to keep them feeding on the plant to produce the nectar. Try to continue the use of the systemic pesticide. One that seems to work well is the Bayer Tree and Shrub Protect and Feed. I have used this on some Austrian pines that are in my yard that worked out well. Also start watering the tree, even in the winter time if the ground isn't frozen, Trees can dry out in the winter if temperatures are warmer than usual and if it becomes windy. Also try an extended watering period that can really soak the soil about every two three weeks. The amount of water will depend on the soil texture. If it's sandy, then you will not have to add as much water during the watering periods, but you may need to water more frequently. If the soil is clay, then water for longer periods but less frequently. Avoid over watering. If it becomes colder, then reduce the watering frequency. Continue watering into the summer. Factor in the need to water based on air temperature and prevailing winds. Again, do not over water. You can remove the dead branches if it's possible. There are quite a lot of dead branches higher in the tree which may be difficult to remove. Dead branches tend to be good entry points for more insect activity.