OK. I've switched to another computer in case it's a problem at my end.
From your initial question, it seems that Jed has two problems: gracilis disease and some form of inflammatory bowel disease which are both common in GSDs.
IBD will prevent him gaining weight and is at least partly responsible messing, along with the effort and pain of getting up and down from the gracilis disease.
Putting an animal to sleep is not a decision to take lightly, and it is clear that you are not doing so, given your question here and your recent visit to your own vet's. On the other hand, when we take on a pet, we enter a moral contract to feed and look after them. The other part of our duty is to make the decision when it is time to put them to sleep. You don't have to take that decision on your own as there are vets like us to help you with that. Often, people feel guilty about doing so, and that is understandable, but you must try not to: ***** ***** part of our
moral contract and not to put an animal to sleep in time is a failure on our part.
That said, I would keep trying with Jed if I were you. I must warn you that the time will come when the pain relief will not keep him pain-free, as gracilis disease tends to progress. In the meantime, I would re-visit your vet as you have not yet run out of options.
IBD, I have had success with a combination of steroids and tetracycline antibiotics. These can be given once daily once stable so your shift work should not get in the way of dosing - this will settle Jed's gut and reduce the messing.
gracilis disease, Tramadol works well but I note that the three daily doses are a problem . Again, talk to your vet when you visit them, as there is a chance you could give a slightly higher dose twice daily. With Tramadol, it's all about dosing to achieve the required pain relief and you are not rigidly fixed to give three doses a day. There are alternatives: you can in these circumstances use a slow-release patch on the skin, much like a nicotine patch, but which release Fentanyl into the system - they are quite a drastic measure, however. You may also find that Jed could get some extra pain relief with ordinary paracetamol, which does not irritate the gut so much and will mix with the steroids.
So you have some options to consider. My advice here would be to try these avenues, and if they work - great. If, however, Jed deteriorates despite all the things you and your vet try, then that will be the time to have him put to sleep.
Pain that cannot be controlled and regular incontinence together are clear indicators euthanasia, and although you may be upset, no-one could accuse you of not trying or not being a good, responsible dog owner.
I hope this helps, and I await any further questions that you have.