The Health Care Power of Attorney ("HCPOA") gives authority to someone to make medical decisions for you if you cannot make them. The HCOA can only become effective at the time you cannot make decisions for yourself. Your AIF, under the HCPOA, will make medical decisions considering the wishes you have expressed to them directly and via your living will. You should name an attorney-in-fact and an alternate attorney-in-fact for both your DPO and you HCPOA, in case your primary choice cannot act.
In addition, the role of AIF can be exercised by two, or more, persons jointly. This can create a check on the AIF's conduct but it can also make it cumbersome for two or more AIFs to have to consult with each other and agree on each and every decision. These are off-setting considerations.