Hi Rose,
I am sorry you are going through this because this is breaking your heart. Also, as a person with a disability living on my own, i wish your significant other could live in his apartment as much as possible. Americans with disabilities have been fighting a lot to get the opportunity to live independently (with all the assistance needed) and in the community instead of living institutionalized. I am not sure about your s.o. But perhaps an advocacy center could help your so to get money from the VA to pay for a PCA (personal care attendant). I will look online and ask my friends in the US and let you know.
About the family of your so, it is not they do not appreciate YOU or your effort. To me, it is they do not love their father at all, they can care less. I remember my mother. She hated her father. She has good reasons to do so. And she never acknolewgded the caring the third wife of my grandfather did to him. Deeply, my mother did not think she needed to thank her (the 3rd wife of my grandfather)for anything, she could not care less. It is very difficult for some people who were neglected by their parents behave properly regarding those neglecting parents. There is lack of interest, they do not care about their neglecting parents and even more, there is a little child inside them that is upset, angry, and resentful. In some way, they do not want their parents to be taken care of. Somehow, it is their turn to be uncaring and neglectful. I do not justify that, but I think this is the way it works .
Sending you a big hug