What to say to him? urgent, family member loss?

My boyfriends brother is disabled and so close to dying. I'm not going to go into detail about that, but he tries his best to stay strong, but sometimes he cant manage it, and bursts into tears in my arms talking to me about it. He sys to me " i cant deal with it, he's dying im going to lose my brother" what can i say? i can't say " everythings going to be alright" because it's not, and the "i love you i'm always here for you" is all i can think of. Help me?