Many of my friends who “served” had the same thing as fathers that I did, PTSD made it difficult to feel “attachment” and “love”, even for our kids. I was lucky enough to have a spouse who helped me through over three difficult decades before getting “help” with the problem. Many were not so lucky. Also, one of the greatest things my kids DID understand, as they grew a little older, was why that distance existed, and both said “it’s okay, Dad.”
Now, after 13 years “service” my son is having the same problems, but at least folks are there for him much sooner to offer help, and guidance. (He also calls me frequently, as Dad has “been there, done that”, and can understand that just listening is often doing, a LOT!)
Sorry to hear your situation, really, Ima, but it explains a lot.