He is claiming he doesnt remember the whole shooting, so no remorse at this point. The police have charged him with up to 110 years in jail or so but, of course, you never know what he might actually end up with.
Sorry if I am overreacting, but this is a sign of generally poor character.
A young relative of mine was arrested for drunk driving as a college student. He too had no memory. However, when he was told what happened, he was shocked, and thankful that the casualties were only parked cars - "I could have killed someone!" he told his parents. It was a wake up call, and he voluntarily reached out to others on campus to work on an anti-underage drinking/drunk driving campaign - he didn't need a judge to do this, but it did favorably impress the judge when it came time for sentencing.
Since this jerk actually killed people - cars and guns, and feels no shock, remorse, or general self loathing for his actions, I get where you're coming from.
If it's the story I think... yikes.
Depending on why he is no longer employed by the big software employer in Seattle and the online recipe company, there may or may not be money. Depending on whether other family members were aware of his instability, and whether they acted reasonably, I suppose someone could try to argue that they might be partially liable. He's only been married 2 or 3 years, so his inebriated state must seem normal to his wife.
Nothing is going to bring your Dad back.
The killer is a self-centered drunk who has described himself to police as a recovering alcoholic. There is no chance of remorse any time soon. This was no accident. He did not accidentally shoot people any more than he accidentally got drunk.
It might be more useful and fulfilling to celebrate your father's life, and work with other organizations that fight against alcoholism.