Normally, after you receive a letter stating that an I-601 waiver has been approved, Ciudad Juarez will mail a DHL packet to him wherever he has designated with the documents that he needs to cross the border lawfully. His permanent resident card will be sent to him within a few weeks. However, if his waiver was pending over a year, he will need to have a re-interview at Ciudad Juarez in relation to his immigrant visa application at which point he will have to submit an updated DS 230 part I, II and affidavit of support. If everything goes smoothly here, at that point he would be provided the documents necessary to legally cross the border. Ciudad Juarez is normally not too responsive to phone calls. Attorneys have an email address at whcih to contact the consulate and they are usually very receptive and respond quickly. There is now a website that allows you to schedule visa interviews and the waiver appointments: http://mexico.usvisa-info.com. They are no longer doing this through the 1-900 numbers used previously.