Sorry to hear about your dad :(
I have no personal experience of this exact situation but as your dad is breathing on his own I would venture to say that his living will doesn't apply as he is not on life support. If he is writing he is, at least somewhat, cognitively aware & will have his own thoughts.
Recovery from stroke is a long hard road & yes, it will take years. Things may not be so good now but it is very early days in terms of stroke recovery. As he is able to move etc., he has something to work with. When you meet with the doctors & therapists what they consider are realistic goals for the medium to long term.
Please keep loving & supporting your dad, he is going to need it.
It doesn't necessarily take years, i have worked with stroke victims who have shown some great improvements. I think your mom is over reacting. Keep in mind the doctors usually tell you "the worst case scenerio".
What exactly does your mom mean about "recovery"??? Does she think he could be in a vegatative state?? Make sure you find out what exactly mom means, before the meeting so that she can get it cleared up when you all meet with the doctors.
Keep this in mind: He will be needing Physical, Speech and Cognitive therapy (most likely). It is imperative that he follows through with this. There are advance therapy's out there that help with his week side. Consider Googling: Bionese and Hocoma.
You will want to get him a neuropsychological evaluation (done by most neuropsychologist). Go ahead and google this and it will explain what it is. If he needs to apply for Social Security Disability Income, have this done up soon and have the neurospychologist put in his evaluation that "he can not work". It won't mean that he can't work forever, although just for now. This helps in getting SSDI.
Check out your local Brain Injury Association, there is one in each state. They have some great tips on what services there are in your state. In Northern Virginia there are case manager to help out.
After therapy, check to see if there are any life skills trainers that specialize in brain injury. They can come up with adaptive cognitive ideas, especially if dad has any memory issues. Again call your Brain Injury Association, they should know.
Remember there are adaptive equipment for cooking and other house hold ideas. So if you dad doesn't necessarily get his full strength back, google adaptive equipment.
Hope this helps. Good luck tomorrow.
I wanted to clarify my statement that it's going to take years. Yes, many strokees make great progress relatively quickly. However even those that have few physical deficits remaining after a year, still battle internally with the aftermath of stroke for years to come. Whilst they appear OK to others, we know we are not the same on the inside. I hope it is something that you never have to really understand - just acknowledge :)