Please advise,
My grandfather's wife will not answer our phone calls or allow us to see my grandfather who has recently become incapacitated and is dying. I am considering calling elderly protection services. Can she legally keep us away from him? Is isolation a form of elderly abuse?

Pretty much yes, she can deny contact.

If you're in fear for his health or safety, you can contact either adult protective services, or even ask law enforcement near his home to check on him (just call and ask for a well-being check) since you know he has health issues and you haven't been able to confirm that he's ok. Neither of these, however, will grant YOU access to him, in person or on the phone, if his legal spouse doesn't want that contact to occur - but they may help set your mind at ease as to his current condition.

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While pointers can be helpful, ultimately the number one lesson in any legal action is: don't take legal advice from books, family, friends, co-workers, police officers, grocery clerks, web sites, or people on legal message boards. The only person who can give YOU legal advice is YOUR attorney.

http://www.aardvarc.org

Does a full med/financial POA make one responsible for finances and debts he inccured/incurs with his wife?

Have you browsed through the information in LawInfo's Free Legal Resource Center to learn more about your issue yet? See: http://www.lawinfo.com/consumer.html. You can certainly try to speak to a lawyer to determine what legal options may be available. In the meantime, you may be able to learn more on your own. Search the "Free Legal Resources" tab, or browse the Consumer Resources. Good luck.