Have you IDed the beetle?
It looks like they are girdling the tree because it looks like there is no bark at the top of the tree. If it was my tree, I would cut off all the dead lower limbs, burn them, and try injecting one of my favorite bug killers under the bark through the holes.
gallon of water
2-3 TBL of dish soap (Dawn)
2-3 tsp of peppermint oil
I would put a soaker hose around the drip line to help de-stress the tree. It is cement bound, so, it probably could use some water. This is where free water from a rain water system comes in, no chemicals added, and you can soak it 100-500 gallons at a time.
I am not an arborist nor do I play one on TV, so, I will not suggest what nutrition you could add. I have seen people water and feed hardwoods back to life in Georgia.
The white cocoons look like spider egg sacks to me.