Susan,
I'm so very sorry for your loss. Alzheimer's is such a miserable disease, because it steals the person from you while you can still see them in body. As you said, she's with your dad now, and they will always be watching over you and your family.
My mom and dad both passed away this last year, and I know how lonely that feels. I'll keep you and your family in my thoughts and prayers as you go through this season of mourning. May the wonderful memories of your lifetime with your Mom comfort you, and may you take even greater comfort in knowing that now she's well again.
Thinking of you,
Grace