Occupational Cultures
Jondc9 raises an important point. Aviation is not alone in occupations which produce an excessive tendency towards drinking the "blues" away. The pressures on Crew are mind boggling at times.
So should it be up to colleagues to be more forward in spotting pilots who are developing a problem backed up by employers who will allow a "penalty free" chance to address the issue. I have seen this approach work in companies and the individuals did benefit greatly from it and retained their positions.