Father of Sam and Dean, husband of Mary. Was a Marine, then a mechanic. Became a hunter after Mary was murdered. Not an easy man to get along with: most of his friendships ended in arguments.

John the Father (SPN family meta)

So, to summarize, it seems that John coped with Mary’s death and the destruction of his view of the world as a relatively safe place by taking action. He prepared himself and his sons, to the best of his ability. His preparation definitely included training his sons in the skills of supernatural warfare, but it also included instilling a mindset that reduced their world down to those that they could trust the most, themselves, and set their minds to preserve each other over all else. Everything was subject to the service of the family’s mission: to survive.