Since you didn't have anything on William, I checked your message history to see if you had anything on a wife or children.You show his birth and death dates and locations, plus name of his mother in a post on the Alabama forum.
Since you know when and where he died, have you obtained a copy of his death certificate?It should show the names of hisparents and state or country where they were born.
Could this be your William after leaving home and making his way to TX?AL to MS was common route when ending up in TX.
1870 census Tishomingo Co, MS:
Stewart, Wm. M., 31, b AL - farmer " Martha, 31, b A " Georg____, 10, b MS (female) " Mary W., 8, b MS " Robert L., 6, b MS " Marcus, 2, b MS " Martha, 5/12, b MS, b Dec Kimball[sic], Wm., 14, b AL - works on farm
Could Martha, 31, b AL, be an older sister????Or, maybe the Stewart family wasneighbors to the Kimbell family???