How do i write a letter of limited power of attorney for some one who is in hospital,?

This person was in a an accident, injuries to his leg and has a broken back, I have used all the money I had to help him. He has money in his bank account, and I also need asset to his home to get documents and health insurance card that he left. The person is out of the country and needs help desperately. He needs to have back surgery, but Doctor's won't do it without being paid. I don't have that kind of money to help him, so I need some type of Power of Attorney to asset his belongings to help him. So, I need asset to his home with locksmith, he lost keys in accident, asset to his savings and checking account at bank. And to help make decisions on any medical situations that may occur. So, how I go about writing a Power of Attorney letter?