I have some friend problems?

So I have some serious friend problems. These problems have driven me nuts. I have gotten into depression just for those problems. So, my very best friend is a girl. Let's name her Emily. And I have another very best friend who is a boy. Let's name him Michael. I also have two other best friends who are really good friends of mine, but not as good as the ones I have already stated. All four of them are actually the same for me, but I just know the first two since I was really young so I might trust them a little more. So I have four best friends. Emily, Michael, Maria and Theo. The problem is that even that I am friends with all of them, they are not friends with each other. Emily is best friends with me, Maria and Theo but not Michael. Maria is friends with me and Emily but knows Michael barely. Theo is friends with me and Emily. Generally, Michael is just a friend of mine. But he's so shy that people don't enjoy being with him usually. I like him. He's by best friend. I truly do, but the rest of my friends don't. He had leukemia recently and now, thank the God, he's healthy. I try to get him out with the rest of my friends but Emily doesn't like that. She was okay the first day I took him with me, just because she knew he was ill, but now she doesn't want him to be with us. Usually I hang out with Emily and Theo. Some other times I hang out with Emily and Maria. And some other times I hang out with Michael and Emily. Maria really wants to see Michael as they used to be classmates and was really worried about his illness. Oh God, this is a really complicated story. Me, Emily, Maria and Michael used to be best friends in elementary shool. Me and Emily went to the same high school where we met Theo. We didn't loose contact with Maria and Michael though. Emily now wants to bring Theo and Maria to be friends, so we can both four hang out. I don't like that. I don't like Michael being left alone. He has gone through so much with this terrible illness. And now what? He's going to be alone again? I don't know, I'm confused. Please, if you understood something of what I said, please help me.