IF somebody gives you some money and you are their health care power of attorney and they told you to spend it can they get you?

The answer depends on many factors. First, the legal capacity of the owner must be such that they are able to understand what they are doing, understand the value of the money they gave you, gave the money of their own free will and do not have need of that money for their own expenses. Giving you the money should not adversely affect the owner. Second, the amount of the money you spent may become a factor if you are challenged about this situation in the future. Scrutiny will be harsher if there is a large sum of money involved.

Your being named as a health care proxy does not give you any general powers of attorney.