Ansy, I am glad you are considering a professional behaviourist. It is not that uncommon for the dog to be taken away for a few months although it is typically 4 months. The main reason for the dog to be taken away is actually to help him. Typically they are taken to a place where they know nothing(including the behaviourist) and that way, they do not really have a recourse to hide back into. He will basically be forced to get used to things. They take them on walks and meet people and teach them to just generally not be scared of everything. Most people cannot do this due to time constraints. I know that I do not have 4-6 hours every single day to work with each of my dogs individually. Behaviourists do extreme socializing that a normal person can't always do. And as most of you know, that takes time. The goal of a behaviourist is to make the dog not be scared or nervous in pretty much any situation. They cannot guarantee that you won't do great during the session and completely fail when they are not around, which only hurts the dog and takes ten times longer to get the dog over it's problems. If a behaviourist can be with the dog 24/7 they know that the dog is getting what it needs to be a well rounded dog. And what you should get back is a much friendlier and better socialized dog that will continue to need socializing but will be better adjusted to fitting around your schedule. I definitely think you should get more opinions but I just wanted to let you know that it is not that uncommon. I would however, ask your vet for a sedative for Piper and once he is "happy and calm" take him to the vets and get him fixed BEFORE he goes to ANY behaviourist. If this guy is trying to scam on a dog, a fixed dog is really no use to him.
Let us know what you decide. Piper is doing great as far as I can tell from what you said. I had Merlin(you may remember the chow mix I had) and he was EXTREMELY undersocialized and abused. Over a period of about a year and a half I had gotten him adoptable. He still had alot of work ahead of him but it really did take him that long to get better.....not great, just better.
Good Luck with Piper and realize that 5 months is really not that long of a time....
Katz is right. My dim bulb, Megan, is just starting to come around after a grueling 6 mos. of her self induced psycosis. She is very Jeckel/Hyde at this point, but I don't play into the drama queen antics, and she is beginning to normalize. You may suceed on your own, I would think it would be a good life lesson if you do it as a study. We are not so different from them.