I am so sorry about your kitty.
I completely understand the comfort she has provided.
On Monday, I had my boyfriend committed to a state facility for substance abusers for the next 30 days. The only true comfort I have found has been in our 4 month old puppy that we got 2 months ago. She's the only one that looks around the apartment for him like I do. She finds the things that smell like him and falls asleep on them. She's also the only one who saw him as out of control as I did. She was there with me every minute of the nightmare we lived through this weekend. Every strange bed we slept in to get away from the apartment, every new place we went to try to get him help, every phone call I had to make - she was there. Although I've always had pets as part of the family, and loved them accordingly, I have never had a bond with an animal like I have with this little puppy. People offer to take her for the night, so I can relax and not have to take her out and whatnot - but they don't understand that she's the only thing that gets me into the apartment. The only reason I can lay in bed at night knowing he's away in a cell is because she's laying there with me. Like me, the first thing she does when she wakes up is roll over to kiss him (well, she more looks to jump on his head... but same idea...).
I can't imagine the pain of losing an animal that has provided so much comfort through pain that, until circumstances like this, one can't even imagine. I am so sorry for your loss.
I hope that, years from now, when our puppy is old and suffering, he is there with me, drug free, as your daughter was, to hold my hand through it all.