78 year old sister lives alone. Has not left her home for 9 months. Doesn't go to doctoror take her medication. She will not sign a power of attorney. I am deeply concerned about her. Any suggestions where I can turn for help??

I suggest that you try and contact your local Office on Aging in addition to calling 211 for community information and referral services.

http://www.helplinecenter.org/2-1-1-community-resources/what-is-211/

Please be advised that unless your sister cooperates, your attempts at helping her is limited to what she will agree to. It's hard to watch someone decline but there is only so much you can do. She needs to be on board as well.