Becoming attached to people is good and tbh when an MMO is involved that's not only a given but a perk. Make and keep your friends, sure some may not be so good, others may surprise you in a good or bad way, but unlike they game they aren't pixels and bytes of information.
If you care for the game you should abandon the sinking ship and move on to a new one.
If you care about her stick through the bad sides and have some fun while you're at it. In WoW fame is measured not in good deeds but in how annoying you are. You can become possibly the best troll guild on your server and laugh about random stuff all day long. At the end of the day if you're not having fun you're not actually playing.
If you want what's best overall I'd say make a new character on a different server, start fresh w/o any kind of back-story and just see how things go. You can always log your toon for her and have your own secret raiding set-up(aka don't roll a shaman on that new realm and you're all set :P).
Edit: I'm sorry to hear of your irl health issues and I wish you all the best and a speedy recovery.