Sudden change in temperment

Question
We have a Chinese crested (Xander) that is an 8 year old male who started growling at my wife this past January. We don't know what is going on and we started thinking it was a dominance issue and he was (in her words) trying to pick her off in the pack.
    The living situation is this: My wife (mandy) rescued Xander 4 years ago from a woman who kept him in a small cage almost 24 hours a day for 4 years. It has been him and her up until December when I moved in. I had of course been around him before for brief for a week here or there (I lived a 1000 miles away at the time and would come visit) and Xander and I got along fine.
  I moved in in December and a few days later brought a female Shit Zu (Maggie, my parents dog) in to live with us while my parents were out of town. Maggie stayed with us for a month and then left. Less then a week later Xander started Growling at Mandy.
   The growling only occurs when Xander is laying down (often sleeping but not always) and is usually when Mandy has left the room and is coming back in. Xander starts growling, barking, and snarling (sometimes snapping in the air) just before Mandy walks in the room (heck I know when she is about to turn the corner by Xanders actions).
  At first Mandy took this as a challenge to her place in the pack and would pick Xander up and restrain him (not hurting him) by placing him on his side on the ground. After doing this for a minute or so Xander would stop growling and hop back up wagging his tail like nothing happened.
  We tried this for a while and we saw no change in behavior. She then started picking Xander up and locking him in the bathroom for 5 minutes till he calmed down. He would stop growling and when we opened the door he was acting like nothing happened.
   Xander has been protective of his food when other animals were near but not myself or Mandy. Lately he growls at her when she feeds him (she takes the food away for a few minutes then tries to feed him again, that usually works).

Oh and he does not growl at me like he does her (he almost never growls at me at all). I can feed him or take away his food as much as I want and nothing. Finally one thing I didn't mention is that since I moved in Xander spends most of the day with me (I work from home) and I am the one who walks him and plays with him during the day.

All I have told you may lead you to say its a dominance issue but one last thing. When Xander starts going nuts he will often walk over to Mandy with his tail wagging while snarling. His eyes don't always seem to be fixed on her. My thought lately has been that he is in some type of pain or distress and he is coming over to "mommy" for help. He has never bitten her even though she has grabbed him while he is doing this over a hundred times (she is understandably frustrated and hurt). I have also noticed that the most common situation for an episode to start is when its cold and he is curled up somewhere. Like at night when Xander is sleeping next to Mandy under the bed sheets and she gets up to use the bathroom. We are almost guaranteed an episode when she makes noise coming back into the room (Xander is still under the sheets).

We don't know what to do. He is getting worse and treating this like a behavioral problem has not helped. Vets don't help and we don't have money for to spend on a behavioralist.

Thanks,
Mark

Answer
Sounds like a dominance issue. It really does. Go to alpha dog boot camp on the web and follow the instructions for establishing and maintaining pack order in your home,. I think you will find it most helpful and will change both your life and your dogs
Good luck
Cindi