I've use OpenDNS at my parents house to help block most of the worst scams, works pretty well.

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.

I would also consider installing ad blocker(s) into his browser (and possibly hiding the icon) along with the anti ad blocker blocker, so not to get those pop ups saying you are using ad blocking. It is what I have done with family in the past in order to help cut down on a lot of that stuff.