former newt

my girlfriend's grandmother is going in for moderately serious surgery (gall bladder problems) in about a week. she is very attached to her grandmother and doesn't think that she is going to handle the surgery well (she's pretty old and pretty sick too) she also has to deal with waiting for a test score that could determine whether the next 5 years go the way she wants. she has a lot of pressure on her right now.

now my problem is i have no clue how to be of any help. i try to encourage her, tell her to have some faith that things will work out, but she just keeps saying i don't understand, i don't get it. now i'm not in her situation, and it's not happening to me, but i can empathize, and i try to be of some use in terms of being an anchor. unfortunately, i slip up constantly and do something that upsets her. for example, she texted me while i was in class telling me that she found out when the surgery was going to be. i called her back after class, but didn't bring up her grandmother. after about 5 minutes, she asked if i had gotten the text, and i said yes. to her, my not bringing up her grandmother made her think i don't care. that's not the case at all, the problem is when she's upset i sort of stop thinking clearly about how to handle her. i thought it would have been good to keep her mind off of her grandmother, but obviously that's impossible for anyone in her situation. i just lost my judgement, and now she's pretty damn upset at me. how do i apologize, and what can i say to help her in any way?