The PIR group for that date is being formed and should be up today. Watch http://www.navyformoms.com/forum/topics/groups-listed-by-pir-date and/or Boot Camp Mom's for more information and the link to join.
If you have not found the PIR group for this division, join the group, PIR 09/07/2012 (clickable link), to connect with others with loved ones training with your SR.
That's the first time I've heard about the alphabetical order. The USPS is the typical reason given. Letters take from 2 to 7 days to arrive once mailed from GL.
Book once you get confirmation of the PIR date for the confirmed division number--typically when you or another loved one receives the form letter. There is still time.
Don't stress over that. Hotel rooms will most likely be the same price next week as this week. Prices for flights change daily, but the hotel prices are a little more stable.
I've given you this info before, but in case you missed it, here it is again:
You may want to check out http://www.youtube.com/watch?v=tvKAhmgkoj4 and http://www.navydep.com/forums/showthread.php?t=433. They will give you an idea of what is happening.
(Group names within this reply are clickable links.)
Is his mom a member of N4M?