Doc's suggested shift in emphasis about PAS makes sense. It's very easy to tilt at windmills when they look like giants. Undoubtedly there are some mental conditions that deserve special designation. PAS isn't one of those. Clearly there are lots of parents who alienate. But to go from that fact to the "fact" of PAS holds up to scrutiny about as well as going from the fact that animals develop reinforced characteristics over time by selective breeding to an undemonstrable belief in the generation of new species through the same process. It's an easy to make but unjustified logical leap.
In short, it's been my experience that we're likely to have more success in situations like yours by working on the results (and sources, if possible) of the other parent's irresponsibe behavior than by trying to go inside our kids' minds and saying we see a "syndrom" lurking there. That's not only unprovable on the evidence, it has the effect of doing exactly the opposite of what we want and need: It pulls more "experts", lawyers, judges, and politicians into our private lives ... not less.
Best of luck. You're a smart guy and you can coolly outthink what's being done to you and your kids by someone who's a lot less smart, a lot more emotional, and a lot less responsible.