Not sure about the tail. Molting takes a lot out of the bird, so just keep an eye on him for anything like a change in behavior, eating, etc. I have a hen right now who was losing weight because she's going through a hard molt. I had to separate her because she was getting picked on. Try feeding him some high protein foods like scrambled eggs, sunflower seeds, to help them grow in quicker. It usually takes a minimum of 5-6 weeks for a feather to grow back.