From what I can see, I looks like possible hail damage?  Have you had hail in your area.  I know you say you water regularly, but the grass around it looks pretty parched!  Are you watering the base only or around the drip line too.  Roots go out beyond the drip line even.  To improve it's odds, if you don't have a ring about 3ft around the tree with just thick mulch, I would encourage you to do that.  Also that  tree support you have around the tree should be removed. A support is generally used a maximum of one year, and less if the tree is stable in the ground.

Fire blight is common on apple tress, but your pictures don't really indicate that, since the leaves that are there aren't browned.