Becky, I may be wrong, but this honestly sounds like one of those scams to get social security numbers. I don't think FT Bliss would be calling her at 5 something to give her routine info and I don't think they notify of injuries over the phone. And, the fact that they didn't know anything (and even if they did, would they have authority to give her that info) also points to someone trying to scam her.
I would tell her to be super cautious until she hears from the proper authorities or your BIL. Anyway to email or IM him to find out for sure?
Keep us posted and tell her, especially when her son is deployed to not trust anyone. I've even heard of these people calling spouses and saying things like we need your social to verify it's you so we can give you info on your injured spouse (pretending to be from the Red Cross) all the while, the spouse is in bed beside them. They try to catch people early in the morning so they can wake them up and get info when they aren't as aware as they would be if they were wide awake in the middle of the day.
Kellie
Love 
