I don't think it's right to let Bob off the hook due to him being from a different generation. Sure, he comes from a time when mental healthcare was crude at best, and racist and bigoted attitudes were commonplace, but he also came from a time when discipline, good work ethic, respect for others, self improvement, understanding the value of money, and just plain common decency were valuable traits for a person to adopt.
He knew enough about Chris' condition to set him up with a monthly injection of free money from the government, yet has seemingly never done a thing to improve that condition. He apparently cared enough about Chris' future at some point when he suggested he take the CAD course, but he obviously gave up on him doing anything worthwhile with his life soon after. Even if he decided that his son was going to fail at life no matter what he studied, he could still have provided Chris with a proper structured home life, discipline, and ensured that he carried out tasks around the home regularly to instill some sort of work ethic.
But he failed to do any of this. He just left Chris to his own devices to alternate between rotting in his room screaming at the internet, and venturing forth into the local community to harass business owners, stalk young women, and generally make a bloody nuisance of himself. All whilst pissing his government money away by buying children's toys and expensive video games and consoles.
The end result is Christian, Weston, Chandler. A truly spectacular amalgamation of many of the worst human traits from the past 100 years. He's got all the small minded bigotry, racism, sexism, homophobia, and just plain lack of tolerance for anybody "different" of a bygone era, whilst he also adopts the selfish, greedy, lazy, entitled, materialistic, egocentric attitudes so common in today's society.