A Lt. Col. Dave Grossman has written at least two books (that I have read); 'On Killing' and 'On Combat' that are very interesting for any person who has a loved one coming home from a war zone.
Other useful reading is 'Deadly Force Encounters; what cops need to know to mentally and physically prepare for and survive a gunfight'. This is oriented towards police but applies to soldiers returning from a war as well.
The military unit should have a support group to help the family understand.
Too many of our fine men (and women) will feel as though they have to grit it out and 'not be a pussy'. This is completely the wrong approach.
Don't misunderstand me and think I am giving the chance for an excuse. The act of killing, especially up close, is unnatural and affects people in different ways.
Some are unaffected but many (perhaps most) are affected and the length of time in the area where the fighting occurs increases the negative effect drastically.
I understand the units are staying together now when deploying home, which is a hugely helpful thing because the soldiers can decompress with their peers who have comparable experiences.
PTSD is an insidious killer of the good life after battle that all of our fine men and women deserve.
"PTSD is real"
I never said it wasn't. Like I said before, he's got alot on his plate right now...including post-war stress. With time, healing and maturity perhaps he will be ready for marriage.