Dear Jen -
Please understand - not only is anger a completely normal part of this grief, but people almost always feel guilty for feeling anger...and then feel even more guilt when they begin to feel better and move beyond grief, even if for just a moment.
My family has lived with a magnified and long-term cycle between grief and anger and guilt. My husband's son ODd in July of 2005 at the age of 19...but he was "revived" by paramedics about 5-10 minutes after he had stopped breathing. I put "revived" in quotes because it was only his body that was revived. His brain was completely fried from lack of oxygen; the entire cortext was dead tissue.
From that day to the present, he has lived in what is called a "permanent vegetative state"....sometimes commonly understood as "brain dead". He may "live" many more years in this state (I should mention here that there was a terrible conflict between mother and father about what to do when he was declared brain-dead. But that's another story).
This situation is almost impossible to resolve emotionally. On the one hand he actually did DIE (because after all, there is not one shred of a "him" left on this earth), and this is a horrible source of great grief, loss, and pain. But in the meantime, enormous pain and drama and expense and continuing heartache goes into caring for his still-breathing body, which is a full-time major endeavor and it is often easy to be furious at "him" that his addiction and mistake could cause so many so much in so many ways. Finally is the guilt: the young man we're sometimes furious at is the most pitiful creature on god's earth and his life and end such a tragedy, so it is very difficult to feel such anger at a "person" who lost not only his life, but his dignity these last few years and for perhaps many years to come. There is also guilt on the days when we don't think about him. If he had died in mind AND body we would understand this as simply moving on and recovering from a loss. But as long as "he" still breathes, forgetting him, even for a day, brings guilt.
Jen, there is so much suffering and pain in some lives. There are more colors of it that we can imagine. There is nothing you can be feeling that hasn't been felt by others. As other wise people here have posted, the emotions will come in waves, and cycles, and sometimes they will surprise us. But always, always, our emotions are our own and there is no right or wrong in what we feel (only in what we DO with what we feel). The only thing that has helped me in this nightmare is my Mindfulness practice, which basically just asks that I be aware in every present moment to what IS...and abide with that, without trying or wishing to make anything be different from what it is. (If anyone is interested in this approach, a good start would be the book by Jon Kabat-Zin called "Full Catastrophe Living" ).
Wishing you continued strength and awareness for you and your family as you mourn your brother.
waxwing