There appeared to me to be an earlier denial on previous threads that Father's behavior at pool party was relevant to SL's disappearance, to her possible depression, to her possible problems with BF/F. IMOO, a denial of alcoholism or a lessening of the impact alcoholism may have had upon the family members, to SL's depression, was evident. That is my opinion only.
IMO, that was a common stance of those from my generation (Drinking heavily was not a big deal.). We now know it can be. Hell, it is. It impacts the family members. Sorry...my Father had mistaken my engagement ring for a beer tab>that's not gonna be swept over.
IF there may have been issues re alcoholism, who knows what prohibitions might have existed towards discussion of mental illness, depression or suicide.
This is my opinion also. Acceptance is a hard pill to swallow and even harder to talk about with strangers. The reason we are all on here though, is not to judge, but to help. We have all been though some things in our own lives which makes us capable to relate to family problems. Knowing my grandfather lost two small children to childhood illness helped me to understand why he dove into the bottle to wash away the pain. It did not mean this was ok to do but it helped me understand the why. If JL did have a problem, I could understand, he lost his entire family in a county he once called home. If anything I feel more empathy for this family by knowing more facts.