It
always hurts when we say 'No' to someone ... even when that 'No' is not answering the call. We think we are the only ones who can help but that is not true. There are other people to call, shelters, hospitals, food pantries, soup kitchens, government programs, rehabs, government housing, etc, etc.
If your brother has made it since March, there is every likelihood that he will make it through this rough spot. It is good for you to know when you are on overload and cannot take on another person.