My sister and brother-in-law currently have a revocable trust that was drawn up in 2010 and gave their son power of attorney over their finances. They are completely in the dark about how he's handling the money and are feeling that he's not acting in their best interests with their resources. I advised them to draw up a new will and cancel the power of attorney. What is your opinion?
There simply is not enough information to give you an answer. There is really not a way to evaluate things unless you know the situation and the purpose of the particular will or trust. Regardless of any of that, if a person is acting as a fiduciary (trustee, agent, etc.) they have a high level of responsibility and accountability and interested parties can ask them to account for their actions.
Their estate plan might be perfectly sound and the "only" problem is a rogue fiduciary. Your sister and her husband can demand an accounting from their son for all financial transactions engaged in by him for their holdings outside the trust. If their son is also the trustee of their trust, they can also demand an accounting as to dealings with trust assets. If he refuses, or if he complies and they disapprove of his actions, they can revoke the power of attorney and remove him as trustee. They will need to give him notice that he has been removed. They will also need to give notices to banks and other entities that have been provided with copies of the trust (or a trust certification) and/or the power of attorney. If their son has stolen or converted money or assets for his own benefit, they can sue him to have those things restored to them.
The attorney that drew up the estate plan can probably assist with these things. If that attorney is no longer available, they should look for an experienced estate planning attorney in their area.
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