Sounds like it might have been hit by lightening. I would wait until the fall to trim it. Most trimming is done in the sping. If you hit green wood it is still alive. Also use dormant oil for the fall. follow the directions on the container. And when you trim you tree spray the ends remaining on the tree with spray paint to prevent bugs from entering. Anytime spraying a tree of that size, you need to be protected with goggles, long sleeves pants & top and face mask & gloves. Also clean off the hand saw when you cut the branches so you do not spread anything to another tree.