My sister has also suggested a number of soups, mostly along the lines of those above. She's also suggesting chia puddings, which are (her words) "smooth, slippery and filling if made with boxed coconut milk."
She has also asked whether your neighbour has any troubles tolerating hot or cold? If not, and especially if she finds cold soothing, "nice cream" is a good option and can have protein powder added for more nutritional benefit.
ETA her followup advice:
QuoteThe Vegan 8 has the most basic vegan recipes, no crazy ingredients. Not sure how many recipes would work but I'd check them online for ideas. Thinking yam/sweet potato dishes would be easy to swallow, palatable and somewhat nutrient dense. Trayce Mcquirter (Ageless Vegan) and Angela Liddon (Oh She Glows) tend to also have healthy and easy recipes with no "weird" or hard to find ingredients. Some "healthy" puddings and such.