Hello @Ceilidh ,
Sorry to hear about your daughter’s massive stroke.
I am not familiar with the slow stream rehab, but my Mum also had a massive stroke back in March 2019 which left her heavily dependant on others and various other complications. Based on our experiences, I would suggest you ask as many questions as you can think of that may help care for your daughter.
There is likely some team that is dedicated to your daughter’s care in hospital and who should ensure a safe discharge from hospital. By that I mean, they should not try to hurry you into making a decision. In our case, we had to make sure the place where Mum was being discharged to (home) had all the necessary equipment and safety measures in place for ongoing care.
We also had a social worker involved etc.
I hope the hospital team (I think they are called the MDT or something like that) will be able to help you. Also, one of the members from this community may also have experience of a condition similar to your daughters.
Wishing you and your daughter all the very best.
Namaste|
After posting the above yesterday, something was bothering me and then having slept on it, it came to me 
There is a recent post here in this forum that relates to your case - link below.
Having thought about it a bit more, though my Mum did indeed have a massive stroke, she was never (and still hasn’t been) offered the slow stream rehab.
As I recall, the MDT didn’t think my Mum would benefit from any sort of rehab (wasn’t given any physio for a very long time).
It looks like the post-code lottery scenario, where you get what you get depending on which part of the country you live. There are disparities even in neighbouring boroughs.
Anyway I hope this helps.