That's only about 150-200 calories....
I think you really need a lower fiber, low carb high fat keto diet, or a non ketogenic Bernstein type, to get enough energy
"I read Dr. Bernstein's book 11 years ago and never looked back. After reading the pages on gastroparesis, I started yelling and cursing. I knew I had it and was mad that my doctor never mentioned that possibility to me. I had had some very close calls while driving 11 years ago.
I 'm now very thankful to Dr. Bernstein and all of the other people who have helped me with my LCHF diet. Without them, I believe that I would not be able to celebrate my 50th anniversary as a T1 in September."
you won't need to go this hard,, but as an example, I have my father on basically a liquid diet, mainly sustagen/fortisip/protein powder/coconut oil/olive oil. His oesophagus is also dysfunctional and a hiatus hernia with his stomach encroaching into his chest. I wouldn't give him low fat yogurt, even if it had no added sugar, applesauce is also on the treat list...it's empty food.
He uses gravity, stands while eating and afterwards, unable to go for a decent walk, but it would be excellent.