Went to see my mom and she is doing better but feeling sad that she will not be here that long since she is 85:( why do I think this way????

My mother is 95, so dry your tears & live every day with joy & gratitude, that's my suggestion. Realize that nothing is guaranteed for ANY of us; while you're worrying mom could die tomorrow, it can actually be YOU that does instead. I always remind myself of that very thing while I try to appreciate each day as the gift it truly is.

Go online or to the bookstore next & pick up a copy of this book, by Eben Alexander, Proof of Heaven: A Neurosurgeon's Near-Death Experience and Journey into the Afterlife

A Harvard-trained neurosurgeon's minute-by-minute account of his own near-death experience - and what he discovered in the heavenly realm beyond life.

On November 10, 2008, Dr. Eben Alexander was driven into coma by a disease so lethal that only 1 in 10,000,000 survive. Seven days later, he awakened with memories of a fantastic odyssey deep into another realm that were more real than this earthly one - memories that included meeting a deceased birth sister he had never known existed.

Dr. Alexander deployed all his knowledge as a scientist to find out whether his mind could have played a trick on him. In its shutdown state, there was no way it could have functioned at all. That left only one conclusion: that we are conscious in spite of our brains - that, in fact, consciousness is at the root of all existence.

The evidence supporting Dr. Alexander's experience transformed him into a believer in God's unconditional love and brought reconciliation to his family - and will upend our ideas about human consciousness and spirituality.
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This book may alleviate any fears you have of death and allow you to live the rest of your life, and your mother's life, with joy & anticipation of what's to come.

There are many, many more like it out there to read, too; this one was extra special in my opinion and Dr Alexander confirmed my feelings when I got to meet him in person at a talk he gave here in Denver a few years ago.

Wishing you the best of luck.

My daughter and I actually talk about death, how we feel about the loss, quite often. I am 80 and she is 60. At this point she is ready for me to go in the sense she feels in charge of her own life. You know, if you are honest, it comes to the point where the old DO become more a burden than a blessing. Death is inevitable. Perhaps it is my career as a nurse that makes me know death is a part of our life, something yes, to be talked about, acknowledged. And a good long life is to be celebrated, not mourned. I think your Mom will always be with you in many ways, just as my own is in my memory so alive. Losing a parent when the parent, or when YOU are you, is a tragedy. Losing them after a good long life is of course still sad, but not a tragedy, and a part of life. We all go there. I think it is perhaps the "unknown" of "how will I feel". You may surprise yourself. When my father died at 92 I felt relief. That I never had to see him sadder, in pain. That I never had to worry for him again, that he was at peace. He had told me he was tired. He was ready. So was my Mom. And indeed, so was my brother, knowing he had a probable early Lewy's dementia he wanted not to live long enough to suffer so many losses of control. So I guess you could say what did I ever have to kick about in these losses.
You really can't know how you will feel. But allow yourself to feel whatever you DO feel. And address the end of life in the way that helps you the most. There is no "right way.
I wish you the best.

First your mom could easily live another 15 years or so, so perhaps it is you that is suffering from some kind of depression, and should seek out some counseling, to find out why you are focused on her death and dying, instead of life and living.
You should be filled with joy that your mom who otherwise was quite isolated is now enjoying her time in rehab, and meeting new people. This should give you and her some insight as to where she now needs to go once she leaves rehab, like perhaps an assisted living facility, where she will be around other folks her age and get to have fun and enjoy whatever time she has left here on earth.
We all are going to die one day, that is a given, and since you say that you pray then you know that when we do die, that we that are Christians are going to a better place when we leave here anyway, and that my dear should give you yet another reason to rejoice, and not be sad.