Hello, that is a difficult situation.  The only thing we can think of to perhaps help these trees is some watering in mid-late summer and fall.  The seasonal summer and fall drought has gotten a bit hotter and the growing season is longer too.  Doug firs have really suffered.  If you water once or twice a month (July-Oct) to replicate a good rainfall event, we feel this may help these trees make it thru the dry season.  A good soaking under the crown, , like with slow drip,  If you use a watering wand avoid soaking the trunk, and apply about two inches.  You can determine that by putting a cup under the watering wand and letting it fill to about two inches.  I hope this can help these trees.