I can identify with the excess drinking as a PTSD symptom as I saw it in my WW2 vet father. Of course, in the 1960s-70s PTSD was not a term in general use. Instead, we had another name for it - alcoholism...and it killed him in 1973 when I was a senior in high school.
And the VA didn’t want to hear anything about that as the time.
He went cold turkey finally on the alcohol. That must have been very hard after years.
He had to go on Zoloft & Xanax for a while later for the mental scars he was left with,but eventually weaned off it.