[CentOS] Auto-installing security updates?

I've been asked to think about setting up an installation for a recently- widowed man. His needs are small - mail, Internet, on-line banking, basically - but his wife dealt with all of it on her laptop and he feels very insecure.

It seems to me that CentOS would be perfect for him except for the need to keep it securely patched. I'm wondering if it's possible to auto-install security updates - for that matter, with so small a set of applications perhaps auto-installing every update would be good enough.

Maybe this could be done with a script run under cron.daily, so that anacron picks it up?

I'd be glad of any advice.

Anne