Speak.  Why won’t you?  You go through each day without uttering a word to any of us.  I understand partially why you’ve chosen silence, as it’s the safer option of survival here.  Believe, I know this; I’m at the same point, myself.  The only difference is that she refuses to allow me that luxury.  Somehow, you’ve separated yourself from us as an act of rebelling in the only way you know how, the only way that really matters to her.  Your academics.  But you’ve brought this upon yourself, you know.  In your mind, this rebellion is the only way you can achieve any sort of normalcy and latch onto that, it’s your way of ignoring everything that’s to come.  The sad thing is that this isn’t normal.  This isn’t right.  This isn’t going to change anything.  This isn’t going to make what you’ve got to face any easier.  You aren’t helping yourself in doing this and you wonder why she doesn’t trust a word that comes out of your mouth.  How can she?  She doesn’t understand your situation or how to help fix it or lessen the pain and fear.  I know she isn’t trustworthy and I respect your silence when being confronted by her, but something’s got to give.  Just because what’s to come is a big unknown doesn’t mean you’ll go to meet an impending doom, or that you’ll have to meet this all alone.  You don’t speak a word to either of us, even when you know that I won’t speak a word to betray your trust.  These secrets aren’t helping anything and only making the impending separation worse.  
Can you explain to me one thing, though?  Why are you making your life harder than what it has to be, when you could be doing so well?  How can you watch yourself fail like this?  What’s your justification?  I’m so tired of all the yelling and lectures that I come home to and then lull me to sleep at night or wake up to in the mornings.  You’re not a bad person, but you’re not showing her that, proving her assumptions wrong, by your misplaced rebellion.