Scared, upset, and sad ??

Tonight my SO dropped on me that he's been unwell. Not like a cough and cold kind of unwell. A severe migraine loss of vision and loss of memory kind of unwell where the doctors are believing it to be a tumor. He still has another test to do but I'm so scared and sad. And upset because he's been doing tests and been feeling like this for almost 2 months. He said he didn't want to tell me because he was afraid I'd worry. I'm so scared. I love him so much I'm terrified. I don't want to lose him! I don't know what to do ??