He's "movin' on up" to heaven.
Sherman Hemsley aka George Jefferson was a TV icon since his groundbreaking guest appearance as Archie Bunker's nemesis eventually spinning off into his own series.
My thoughts exactly. If I remember right, the character of George Jefferson had a son Lionel who was the same age as Meathead. I thought he (Helmsley) was in his mid 50's back in the 70's (35 years ago). Obviously he just looked a hell of a lot older than he was.
It's like if you ever saw Braveheart, the actor who played Hamish's dad (now on Game of Thrones) - James Cosmo was in fact only 7 years older than Hamish (Brendan Gleeson)