Draw a selection around the unfocused area. Hit the Sharpen command, then go to Filter>Fade Sharpen, and reduce to 40%. Make a new selection, very similar to the original, and repeat. Do this a grand total of three times, or four times. Then, down-size the final image to about 1600 pixels wide and apply an overall Unsharp Mask that yiou think is appropriate. I have done this many times. The key is working on the big file, and fading the sharpening after each pass,and down-sizing the final file,and then sharpening that.
This is not a perfect method, but on a furry animal, it will work reasonably well,especially if the final image is down-sized.