Like everything else, alcoholism runs along a continuum of instability, to borrow your word. I never really categorized my father's alcoholism once I was old enough to understand it. But I knew he only drank beer and pretty much only after getting his paycheck on Friday and then Saturday too. I had a sense of feeling lucky at least that he didn't use hard liquor or drink constantly or beat us. He always had a good union manufacturing job and provided well enough for our family. My few friends who met him would think he was great (he treated strangers much nicer than family). So while he may have been "functional" in some areas of life, he was most certainly dysfunctional in profound ways as a father which deeply affected me emotionally. My therapist is an avid proponent of EMDR which is used to treat PTSD. For whatever reason it didn't do much for me although I am open to trying it again. My suspicion is that is has a more obvious benefit for those who've suffered more severe psychological trauma.