Do you really think your W has any suicidal thoughts? I have heard that if people start to talk about it there may be a risk they might do it. She is not handling things very well and she has the health scare to worry about too. If you think there may be anything to it you should take it seriously. Perhaps suggest she talk to someone.
The porn story thing: I think you should let her see it as long as it is something you think she would like to read. I mean nothing she might find disrespectful. They say women are more turned on by erotic fiction than visual stuff. Personally not sure about this, but I still think she would like it. Give it to her when she is in a good mood. I think that will certainly show her you have been thinking about her and that you still are interested in her. Hey and another thing you should call it erotic fiction not porn!!
Maybe have another go at persuading her to go with you to your family for Thanksgiving. Say you understand she misses her bro but you would really like to have her there. Even if she decides to go see her brother after all at least she will know you wanted to be with her.