Visitors Insurance

Sorry for using this to pose a question. I couldnt figure out how to use the discussion forum. My parents are planning to leave for USA in 16th/17th midnight. I need to buy insurance online. Protection America from IMG seems to be good. Can I buy it now from here? Or should I get somebody in US to buy it since they need to mail the certificate etc. They also send the ID card by mail. But I cant get it to India in time. The "Print ID card" link in your site for says "possession of this card doesnot carry coverage" when I open it. I understand that all policies are effective from the time they leave India. How can they seek medical help en-route if an emergency arises and they dont have a card or if the card doesnt guarantee coverage. Any suggestions? Please reply to my email id. AND PLEASE TREAT THIS AS URGENT.