Hi, EndGame,
Thank you for the updates. I join the many who are keeping you and your family in my thoughts and hoping for the very best possible outcome. The days ahead are likely to present ups and downs -- take good care of yourself.
From the Department of Unsolicited Advice: I think you're being a good brother when you contemplate moving in with your sister. Perhaps it's possible to keep your own residence intact, too. If -- and only if -- she is in for a rough time, you'll need to practice self-care, too.
Of course, nothing has to be decided right now. Give yourself time to think things over further as more information becomes available to all of you.
I've spent a lot of time on hospital duty with my mother. It's draining. Do some nice things for you over the next few days. Even breaks from work/hospital/family with a nice cup of coffee and the NYT will feel like a much-needed respite.
All the best.