So far I have just installed Ghostery for my parents, since it doesn't break most sites, and they are sharp and AFAIK don't visit sketchy sites. But I have seen one grandfather turned into a Fox Geezer and ripped off by scammers, despite his children trying to clue him in, so I suspect I will have to do something more aggressive at some point in the future. Thankfully, I think they have enough distrust of humanity that I should have no problem installing a firewall.

Also, they thankfully show no interest in social networks.