I am so sorry to hear that your fiancé has been let go. I can well imagine it is very stressful. The job market being fickle at best cannot be of much help either. My only suggestion would be some smaller things..
Most of all please don't blame yourself. If there was something you could do I know you would! It isn't your fault. If you were working, you would likely be causing accelerated damage to your body. That would only make things much worse for your family in the long run.
I hope you are able to get everything ready in time. I am so terribly sorry you are getting hit with this. Please know you and your family are in our hearts and prayers.