i overlooked the most obvious possiblity that he might be going to Nepal after filing Nepal as his country of prosecution, i am sorry, but if his family is in India, Canada, thailand or any other country then he should be fine with his greencard( the gentleman didn't state that he's going to Nepal, who knows where his family is).. yes you're right an asylee going to his/her country of prosecution can be very devastating interms of his papers in the USA for the exact same reason you explained above.  my understanding of advanced parole is that it is to come back to the USA from a short trip abroad. Since he already holds a green card he should not need an advanced parole. Asylees , just like refugees can also file for Refugee Travel Doccument (RTD) if they don't have a green card. Again, i am not an expert in immigration matters, i am just trying to inform and learn, i maybe totally wrong.. the article above is published the same day i posted. i emailed the lawyer and he sent me the link to that article. the weblink below also contains very useful informations..

http://forums.immigration.com/showthread.php?297900-I-am-no-Terrorist-any-advice/page7