Answer: It is always okay to remove twigs and branches that are totally dead, but you would not want to prune live wood in the late summer or fall. The reason for this is that it would encourage fresh new growth that would not have time to "harden" before winter. For the same reason you would not want to fertilize now. Also, it is not a good idea to encourage new top growth in severely water stressed plants.
If you think a branch is dead, begin at the tip and trim off a piece; examine inside it for signs of green. If there is green, then the branch is not dead. If the inside is totally brown and/or the tip is so dry it snaps off easily in your fingers, then that part is indeed dead and can be removed. Work your way down from the tip toward the center of the plant. With a little practice you will be able to pretty much tell from the outside appearance whether or not a branch is truly dead.
If you want to fertilize, do it next spring using a fertilizer formulated for acid loving plants and/or azaleas and rhododendrons. Be sure to follow the label instructions carefully -- adding more than the recommended amount will not be beneficial to their recovery.
Finally, the best thing you can do for your azaleas is to make sure they receive enough water from now until the ground freezes. These plants like a moist yet well drained soil (meaning not soggy) and are shallow rooted so they benefit greatly from several inches of organic mulch spread across the root zone. Water them slowly and then dig down and see how effective your watering is (or isn't) so you know how much to apply at a time. It is also better to do a slow soaking than daily light sprinklings. Good luck with your azaleas!
Q&A Library Searching Tips