If a low-salt pre-cured pork were used, the high-salt content sausage could be uncased and re-ground, but I just don't see how the already made sausage texture will reform after being "broken" by grinding again. If you take a meat mix and ferment and dry it (as with old-world style traditional summer sausage), or chemically cure the meat mix (as in modern techniques for "tangy" sausage) and then case the meat and hot smoke, the proteins would have formed a tight bond within the casing giving the firm texture you notice when you slice it. Once this bond is broken down, getting a second grind to reform this bond could prove to very difficult at best, as the proteins have already been developed the first time around.
If this sausage has been cold smoked it probably would not change the composition much, but if it was hot smoked and ready to eat, you'll really have a mess...nothing but crumbs after it's reground. My past experience has been that fully cooked meats won't bond together, though with the addition of more freshly ground raw pork, there is a chance that he can pull it off. The second processing/smoking of the original meat just seems like a bad idea...I'm not sure about this.
It's worth a try, 'cause short of using it as ingredients for other dishes as I mentioned on your earlier thread, there's not much else that can be done with it, IMHO.
Hope it works out, and please do let us know the results, good or bad...it sure has me wondering.
Eric