I don't think too much of gym stories, but I heard that Liston was so old, he sparred Luis Ortiz, when Ortiz was only in his early 60s (28-29 years before he fought Deontay Wilder).
The other brother was called Curtis Liston. He was born in 1929 a year earlier than the Charles Liston who registered as ten years old in 1940. Who knows, it could work. Sonny is just a nickname. If there were no birth certificates how official were their names? My guess is whoever Sonny was, he didn’t know who he was or how old he was. He just said whatever suited the situation. Tobe Liston died in 1948 probably from the effects of a hard sex life. He sired 22 kids.
Time is a man made construct, an abstract concept. Are we really alive? Do we really die? Sonny was possibly created from the centre of billions of stars, billions of years ago, and he will exist in some form until all of the universe is no more. Liston is still with us!!!
The census from 1940 pens him at 10 years of age. He himself via his marriage license stated he was born in 1928. There is no reason other than wanting to believe something without any supporting evidence to believe otherwise. When he stepping into the ring with Ali in 1964 Liston was in the range of 34-36 years of age.
There is no such a thing like "Sonny Liston". They were twins. You could see what happened when his brother came for the rematch with Clay.
Sonny Liston's family was enumerated by a census taker on April 8, 1930. But Sonny doesn't appear on the census that year. Moreover, the youngest Liston child, Curtis, was only six months old at the time. As a result, it is probable that Sonny was born after June 1930 if Sonny and Curtis had the same mother. - Chuck Johnston
At the end of the day sonny did not live long enough to reach 42. Even if sonny was curtis liston or charles liston.
IMO this the most plausible scenario. Liston was past his best when he faced Ali, but not quite a shot fighter.