If I understand correctly, Broken Heart Syndrome feels like a heart attack. Are you having such symptoms--chest pain, difficulty breathing? If so, I'd go to the ER because the cause isn't really known. If it isn't that physical, grief and fear can still be extremely painful. I'm so sorry to hear about your brother, and hope for the best for him. When I was widowed, the first thing I did was go to my PCP and talk to her. She ruled out anything physical, and treated me with care and compassion. Then I attended a grief group, which really helped. Is there anything you are doing that is helpful to you?