Sorry, it's been a crazy week. So far, the Reglan seems to be doing the trick. Vomiting is much less. Not completely gone, but more like once a week rather than nearly every day. It's possible the steroids are also kicking in a bit to help, as well. He was off the pepcid for a couple days while I was away on business, and it make no difference whatsoever that we could see, so I'm not making him miserable by shoving it down his throat if it doesn't actively help.
He's in pretty good spirits so far. Hopefully he'll stay that way.
My vet is pretty great in that he doesn't try to talk me into treatments that aren't going to help. In fact, he flat out told me that if it was his cat, he wouldn't try chemo, either. And he said that doing the biopsies wasn't necessary, since if it's not IBD, the options are grave.
Murphy still isn't putting on weight, but he's not losing it, either at this point. And he is old. Something like 90 in human years. We're lucky he maintained his youth for as long as he has, really. 
Well, first, I'm pretty sure we need a few pics of the boy, just for advisory purposes, you know
Okay, so your vet sounds great.
My vets are great too, love them, but one area I think is very lacking--the fault of our veterinary educational system, not the of the vets themselves--is nutritional education.
It sounds like you've been on a similar medical/diagnostics journey as I have with my old boy Mojo, and that the vet advice has been similar as well.
Where I ended up turning was to the focus on healing the gut, insofar as was possible, after the years and years of damage that I didn't realize was happening.
Frankly, my vets were skeptical at first, but are now really on board.
This article explains it far, far better than I ever could, but the short version is that all the chemicals, grains, fillers, preservatives and so forth in commercial pet foods cause damage to the gut lining--that inflammatory reaction is what you see on x-ray and US, with the thickening of the intestinal walls.
Here's the article--scroll down to the introductory diet section for a quick jump start on the program, but the whole article was very informative, for me--your research may have already covered this, but I learned a lot about how a healthy cat's GI system works.
http://feline-nutrition.org/health/feline-inflammatory-bowel-disease-nature-and-treatmentSo, for Mojo, we do some of the same things you're doing with Murphy--motility agents like Reglan, antacids, steroids as needed--BUT (knocking wood furiously) his need for those has dramatically decreased with his new diet.
However, there are a few things I haven't seen mentioned that may benefit Murphy--we found supplementing B vitamins to be very helpful, some done by injection, others added to his food.
Also, make very sure that any of the feline herpes viruses have been ruled out, because Mojo was also suffering (silently!) with oral ulcers due to calici virus--even though he has a solid vaccination record and is indoor only--one of the shelter kitties apparently brought us that gift home. Sigh.
But, anyway, you have to make sure those ulcers are healed, if present. Mojo is on L-lysine now, to prevent any further flare-ups.
All in all, I really think this might be very hopeful with Murphy--partly because he hasn't lost much weight yet--Mojo is at a critical point with his weight loss, sadly, and if he didn't act so happy and active, I'd have likely made the decision to euth, based on his severe weight loss alone.
I don't want to hit you with a novel, but if after you check that article out, you want more tips or details, just say. It may be you can heal his gut since you're catching it now--I don't believe that is "false hope," at all, and at any rate, it's a very healthy way for kitties to eat in general.
Mojo was diagnosed not last May, but the May
the year prior--and is still going strong, despite his skinny self
