Hi MNS1979
Welcome to NT - as you've found there's always someone around to help with queries so I'll throw in my two cents worth.
Sorry to hear your husband has had such a 'run around' with careless physicians. As others have said - time to find a better one.
Re the possible diagnosis here's a couple of other possibilities to consider:
1. Gluteal Tendinopathy (similar to piriformis)
2. Trochanteric Bursitis
Here's a link to a website that has an explanation. I realize the website is promoting a specific clinic and I have no experience of that clinic nor am I endorsing them - but the information on the website is presented in a clear and easy to understand way.
http://physioworks.com.au/injuries-c...l-tendinopathy
If you scroll down near the bottom you'll find a list of links to related conditions - the last of which is Trochanteric Bursitis
If neither of these seems to match your husband's condition then another possible (although less likely) condition may be Pudendal Neuralgia.
Another link:
http://www.pudendalhope.info/node/9
MNS - hope this is of some use. Let us know how you get on with your quest for treatment.