
Next to, say, the HIV virus, Diabeetus is one of the most deadly diseases you can get. Unlike HIV, however, you will constantly be the butt of every joke couresty of your peers. As a 4chan.org meme, it was a major success. So much so that it earned a place on the /b/eatles. It's a great option to start mini-memes and reaction memes.
In 2006, diabeetis.com was created, including pictures, videos, and a few games. Of course, the site is rendered useless by most because it's spelled "diabeetis" and not "diabeetus".
Wikipedia did not take too kindly to Brimley:
Internet Movie Database says that Brimley was a fan of former president Howard Taft. Apparantly, to show his dedication to Taft, Brimley had plastic surgery performed on him and contracted the beetus in '79 to look identical to him. They took this fact off the site, for some reason.

Some remember Brimley for his illustrious acting career, appearing in such movies as The Thing and Cocoon. Others remember him as a Marine who served for three years in the Korean War. As for everyone born in the late 1970s onwards, we know him as a supporter for Liberty Medical/Quaker Oats, an overweight has-been whom we laugh at for the misprununciation of the word "diabetes", and as an Ewok in the made-for-TV Star Wars movie Ewoks: Battle for Endor.

Wilford will die with the knowledge that he was not a respected actor, but rather the butt of everyone's joke.
Case and Point
Exhibit A:
Exhibit B:
I rest my case.
Cracked Talk on | Diabeetus