I am sorry about your job loss and the death of your mother last month. That is a lot of transitions in a short period of time. It sounds like you are very clear that you don’t want to move home, if at all possible. So my question for you is why do you care so much about pleasing your brother? You are 41 years old and the great thing about being an adult is that you don’t have to have discussions that you don’t want to have, and you don’t have to do anything you don’t want to do. You can’t make your brother understand your point of view, but you can show him that your finances are not his business by not discussing it with him, and by letting go of trying to gain his approval. What are you afraid of if your brother is mad at you or thinks that you are selfish right now?
It sounds to me that he’s less worried about your money issues and more worried about your dad who now lives alone and just lost his companion. Having you move home may be an easy way to alleviate his worries about your father living alone because it makes sense logically to him. “You’re unemployed so why don’t you move home to save money and take care of dad?” seems to be his message to you. You are both talking about the topics instead of the emotions that go along with the death of a parent and concern about the parent who’s left behind.
I suggest that instead of trying to get his approval or convince him that it’s not good for you to move in with dad, you cut right to the core issue which seems to be exploring together how the two of you are going to work together to help dad through his grief and loneliness, and to make sure that he is safe and taken care of, and how you can support each other at this time of loss.
Take good care of you and yours.