Also, some health care directives are state specific. I know that the one used by my HMO is one for our state in particular. You might be able to get that form from your doctor.
If there would be a fight if the worst should happen to you (over "pulling the plug" or other crucial decisions, say) between your blood relatives and your boyfriend, be sure to talk to your family and tell them what you are doing. There have been some awful lawsuits over who gets to handle the medical decisions for someone who is not in a position to make their wishes known.
Here's an online site that will do your medical power of attorney for you.
I don't think you need to have an attorney to do it - you just have to complete the legal forms. There may be a charge associated with this.
Do you suspect anyone (parents) will fight you over this? If so, you may want to get an actual attorney.
http://www.legacywriter.com/dpoahc.asp?src=g15medical7&gclid=CJrik5Ch-qoCFcw42godtlA7BQ
Sure. As long as your signature is notarized and he is over twenty-one.
But you need to straighten out your legal terms. I suspect what you want to do is provide him with a document to access your medical records and speak with your physician, or to act in the event you are mentally incapacitated.