Hi, I'd like to help you with your question.
It does sound like your mother is addicted to Oxycotin and she does need help. Your insight into her problem is very good. Addicts will almost never recover unless they themselves want to recover. They are in denial about how addicted they are or even that they are addicted at all. Talking to them, trying to plead with them or even attempting to force them into treatment does nothing. Unfortunately, that leaves the person's loved ones to suffer without many options to help.
However, there may be something you can try with your mother. There is a drug and alcohol technique called an intervention that may help break through the denial your mother is in about her addiction. An intervention involves getting your mother's family and friends together (those aware of her addiction that want to help) and with the help of a therapist or intervention specialist, you all confront your mother about her addiction. This can help her break through the denial and see that she has a problem. If she can do that, then she most likely can recover. Here is a link to find an intervention specialist:
However, you also can work with a qualified drug and alcohol therapist for the intervention. To find one, contact your local rehab facility or community mental health center. They will help you find someone.
Here are some other resources that may help you and your father:
Addict In The Family: Stories of Loss, Hope, and Recovery. by Beverly Conyers
7 Tools to Beat Addiction by Stanton Peele
Love First: A Family's Guide to Intervention by Jeff Jay, Debra Jay and George
You can find these books on Amazon.com or your local library may have them for you.
I hope this has helped you,