Your father has misunderstood what a DDOS attack is and how it works.
Wikipedia gets this one about right, though generally I don't regard Wikipedia as a reliable source.
DDOS attacks are launched by remote and IP addresses are used through infected "zombie computers." That is, the computer operator most often has no idea that his or her computer is being used in an attack. And the network that includes the IP typically does not know either.
The attacks launched against the Ross Institute Web site were largely done from Eastern Europe, Romania to be precise.
There were some IP addresses involved in the UK, though very few.
Your father's IP appaently was one of them and it was therefore blocked from accessing this site. That status may eventually change.
Blocking out attacking IP addresses is a typical response by security to a DDOS attack.
A full and detailed report has been filed regarding the recent DDOS attacks with law enforcement.
DDOS attacks are unlawful and a criminal offense.
Hopefully the person or persons behind the attack will be caught and prosecuted.
Meanwhile, the hosting company responsible for serving this Web site and message board has effectively ended the attacks and the site is easily accessible, to those outside of the IP addresses previously mentioned.