poor sonny

We are off to the vet with Sonny on Thursday.... He was treated for Giardia (with Metronidazole) when we brought him home.  His diarrhea didn't clear up, and then I saw some sort of worms in his feces, so he was treated with Panacur.  Everything seemed fine, but he was still have loose stools, and I'm guessing it was from stress.  The vet tech at the rescue wanted to treat him with the Panacur again, to make sure we got everything (parasite- and Giardia-wise).  He's also been on a bland diet (ground chicken/beef and rice) and that hasn't done anything either.  It's been over a month and the poor dog hasn't had one solid stool.

I have to think it's a big possibility that Sonny's loose stool is stress-related.  This poor dog is in a fairly constant state of panic and anxiety.

I've asked that we talked to a veterinarian about putting Sonny on an anti-anxiety medication, but I haven't gotten a straight answer.  I've been told Sonny should see a trainer for an evaluation first, and of course, the rescue uses an aversive trainer and they want Sonny to see him despite my objections.  I'm not sure how that will help, but doG help me, if he does anything force- or flooding-related, there will be a problem.  This dog has been through enough and I am not going to risk this dog or ignore science-based research on learning theory and behavior modification to appease someone else.

What do they think this will accomplish?  Why does an aversive trainer need to see the dog's fear in order to understand the need for a different approach?  What I've said about him being so afraid when he hears noises outside that he literally attempts to run while pooping, and in effect, poops on himself, isn't enough to warrant talking to a veterinarian about his mental state and the damage the anxiety is doing to him?
 
It's not fair that this dog is so anxious all the time.  I can't imagine the effects on his mind and body.