Wow, I'm sure you uncle is acting out of love, that he feels it's better that she doesn't lose hope and if she knew she may give up. This I can understand. But in her condition yes she must know the end is near. I think she should know. I think it's best to have a clear picture of what is going on and what is happening. That doesn't mean there is no hope, but she will be able to prepare herself for things that can happen. Everyone I know who has died from cancer has been grateful to have had a chance to say what they need to say and do what they need to do before they go. Not everyone gets that chance, and having all this in order really can bring peace of mind. I know your aunt can't communicate well, but maybe there's some things she'd like to write to people, some final wishes of love she's like to remembered by. I don't know the best way to approach this, but he may need to hear it from your whole family. My best wishes to you and your family.