i think you will be an excellent nurse, nathandh. great nurses are also compassionate nurses... and of course it would be difficult to see your brother like this. likewise, the memory of his accident and what it was like to see him in the hospital probably was a hard memory to shake, so it's also understandable that subsequent visits would be a little difficult as well, although not as bad as the first. i know 110% that i am called to be an rn... and yet, i think i would completely pass out or go into hysterics if my patient was, say, my brother, my mom, or my husband. i could never do it. however, i've shadowed several nurses - the most recent in a level iii nicu - and i absolutely loved it. in fact, i felt frustrated that i didn't have the skills to jump in and help while i was there! so, i think it's an emotional connection that made being in a hospital so difficult.
the earlier poster who suggested a job shadow - try that. there are lots of areas of nursing, so don't feel you have to do, say, trauma icu if that would be too much for you. also, being an rn doesn't necessarily relegate you to a hospital - there are so many other places that need nurses!
i hope this helps... and we're always here if you have other questions or doubts.