Oh I'm so sorry. I hope you can enjoy the next few days and the little one is doing better.
Not going to lie, it's kinda harsh that she was fine with everything being paid for but didn't jump in at any point to help. It'd be one thing if you planned the trip together and she was paying her way to chill with you all. But i can imagine that adding to the pressure for sure. I get irritated if we go on a trip or camp and someone decides to just lump it while others work! It'd be ten fold if I had a sick baby, I mean, that's just common courtesy. And working together is how you form those bonds, even if it isn't your favorite person...she opted out on that and it really sucks.
Now go enjoy. Cuddle that family and pick your flowers 🙂