Don,
You have my empathy & support.
In 2007, I had 2 of my 3 boys deployed.
We knew more about #1 son's deployment as he was stationed here in Colorado at the time. My #2 son called from his base the day before he left to tell me he would be gone for 6 months. Yes, I knew he was going, but not when.
The hardest thing I have EVER had to do was watch my first "baby" climb on that bus. He was in the first group who went over planning on 12 months and ended up being over there for about 16 total.
The "secret" is for security reasons, and is understandable. When they get over, they are allowed phone calls home and also email time, However, please know when there are casualties to the group, ALL communications are shut down. If you do not hear from him for a few days, breathe & pray. I always told my son that I didn't need a novel, just a quick email to say,
I'm busy, but I'm okay. would suffice.
Take care, stay busy, and love your DIL & Grandbaby for him, because it is the best way you can help him know they are taken care of.
God Bless & Happy Quilting,
Susan