My wife lost her mother to cancer in October and she was in a similar situation to yours where she was at home during the final weeks. You know the end is coming, but you are never totally prepared for the day and the finality of it.
It is times like this when our faith in God is the only thing that gives us the strength to go on. Knowing that the Lord has a better place in store and knowing that we are part of a bigger plan kinda brings some sense to all of it.
The thoughts and prayers of my family are with yours.