Answer by taking a quote from the following article:

Redd Foxx was born John Elroy Sanford on December 9, 1922, in St. Louis, Missouri and raised on Chicago's South Side. His father, Fred Sanford, an electrician and auto mechanic from Hickman, Kentucky, left his family when Foxx was four years old. He was raised by his half-Seminole Indian mother, Mary Hughes from Ellisville, Mississippi, his grandmother and his minister. Foxx attended DuSable High School in Chicago's Bronzeville neighborhood with future Chicago mayor Harold Washington.

Foxx achieved his most widespread fame starring in the television sitcom Sanford and Son, an adaptation of the BBC series Steptoe and Son. He used his starring role on Sanford and Son to help get jobs for his acquaintances such as LaWanda Page, Slappy White, Gregory Sierra, Don Bexley, Beah Richards, Stymie Beard, Leroy Daniels, Ernest Mayhand and Noriyuki "Pat" Morita.  The series premiered on the NBC television network on January 14, 1972 and was broadcast for six seasons. The final episode aired on March 25, 1977. Foxx played the role of Fred G. Sanford ("Fred Sanford" was actually Foxx's father's and brother's name), while Foxx's co-star Demond Wilson played the role of his son Lamont. In this sitcom, Fred and Lamont were owners of a junk/salvage store in Watts who dealt with many humorous situations that would arise. The series was notable for its racial humor and overt prejudices which helped redefine the genre of black situation comedy.  The show also had several running gags. When angry with Lamont, Fred would often say "You big dummy" or would often fake heart attacks by putting his hand on his chest and saying (usually while looking up at the sky) "It's the big one, I'm coming to join ya honey/Elizabeth" (referring to his late wife). Fred would also complain about having "arthur-itis" to get out of working by showing Lamont his cramped hand. Foxx depicted a character in his 60s, although in real-life he was a decade younger.  Demond Wilson had responded if he kept in touch with everybody from Sanford & Son; esp. the series' star, himself, after the series was canceled: "No. I saw Redd Foxx once before he died, circa 1983, and I never saw him again. At the time I was playing tennis at the Malibu Racquet Club and I was approached by some producers about doing a Redd Foxx 50th Anniversary Special. I hadn't spoken to him since 1977, and I called the club where (Redd) was playing. And we met at Redd's office, but he was less than affable. I told those guys it was a bad idea. I never had a cross word with him. People say I'm protective of Redd Foxx in my book (Second Banana, Wilson's memoir of the Sanford years). I had no animosity toward Foxx for (quitting the show in 1977) because I had a million dollar contract at CBS to do Baby I'm Back. My hurt was that he didn't come to me about throwing the towel in - I found out in the hallway at NBC from a newscaster. I forgave him and I loved Redd, but I never forgot that. The love was there. You can watch any episode and see that."

what was his relationship with Lamont like?
When angry with Lamont, Fred would often say "You big dummy"