Oh, Bonnie, my heart goes out to all of you, especially Shirlee. I am sure you know it will be best when the Lord calls her home. Meanwhile, to keep her comfortable and loved is the best, kindest, sweetest thing you can do.
Rehab is not allowed to keep someone if they don't show improvement. A costly nursing home will keep her but many will not give the care that would make her last days comfortable. I commend all three of you for being willing to care for her. It speaks so well of Dale who cares that much for his mother.
You will be daily in my thoughts and prayers.