I'm sorry to hear of your trouble. I started having issues with swallowing in November of last year and was diagnosed with 6cm Barrett's Esophagus after an endoscopy. I've been fighting with this for several months and have gone through so many diagnostics - looking at everything from the BE to potential neurological issues - that it is frankly ridiculous at this point. One of my doctors suggested that I may be having esophageal spasms due to the erosive damage and he prescribed 1mg Xanax to help with that, as well as my overall anxiety concerning these issues. Curiously, it has helped the swallowing a bit...though I'm still not able to eat dense foods like steaks any more. I take the Xanax as needed, but honestly I'm not a big fan of staying on it for too long.
From a dietary perspective, everyone is different - I can only say what I've done that has helped me with the reflux. I've made several changes over the past several months - e.g., dropping caffeine/soda/alcohol completely, switching to a paleo-style diet focused on fruits, veggies, eggs, fish, and other whole foods (nothing processed), supplementation with omega and krill oils, colostrum, glutamine, and spirulina...etc... I learned that bread is one of my reflux triggers, so I've cut it out completely. This has been a really a tough one, as I'm a huge fan of breads and pastas. But the bottom line is that they give me problems every time, so they had to go.
I went through a period of time where Boost was all I could handle. As a result, I dropped a lot of weight in a short time. It took me a while to get to a point where I could eat full meals on a more regular basis, but I still have a smoothie for lunch every day to keep my protein up and also get my supplements in each day. So to help with weight gain, that would be my recommendation. Make a big smoothie each day with fruits, protein powder, and healthy fats to keep the calorie intake up. Here is an example of one that I make:
2-1/2 cups filtered water
1/4 cup unfiltered apple juice
1/2 cup plain unflavored kefir
1-1/2 scoops BSN Syntha-6 protein (strawberry)
1 Tablespoon Perfect Food Raw Organic Greens
1 to 2 Tablespoon(s) Udo’s Choice Oil 3-6-9 Blend
1 to 2 Tablespoons heavy cream
1 Tablespoon honey
5 to 6 medium strawberries
Handful of blueberries
6-8 ice cubes
It usually runs about 500-600 calories per serving, I believe. Anyway, that's just one idea. I know how difficult Barrett's can be, especially when paired with swallowing difficulties. If I could recommend one other thing, it would be to take a look at a paleo-style diet. There are many variations out there, but I can say that following this type of approach to eating has really knocked out my reflux problem. Now if I could only get this swallowing issue to clear up, I'd truly be back to normal.