Hi
Welcome to the forum !
Currently they are working on Aug - Oct 2010 file transfers. People whose files were transferred in these three months are now receiving requests for IMM Forms, Re-PCC and Re-Medical respectively.
IMM Forms: They ask the applicant to fill out these forms for updated information.
Re-pcc: They ask for an updated police clearence certificate.
Re-medical: Usually the medicals are expired by this time so they ask for Re-medicals.
They usually do the initial review of the application after 9-10 months of the file transfer. So it looks like they won't review your daughter in law's file till March 2012. Meanwhile, ask your son to keep collecting proof of communication with his wife; i.e. phone bills/logs, emails, chat, video chat logs/screen shots, money transfer receipts/funds transfer. If he visits his wife this year or early next year, than their photos together, his boarding passes, entry/exit stamps, restaurant bills etc. Basically anything that would make them believe that the couple is in contact which shows the genuinity of relationship. He can send the proof voluntraily by Jan 2012, or wait till they ask for it. Some people send it voluntraily, some don't, so its totally his call.
Hope it helps