Caleb Willingham, estranged husband of “1000-Lb. Sisters” star Tammy Slaton is dead.    TMZ reported that Caleb’s stepmom, Shirley Willingham, confirmed the sad news but couldn’t provide further details or a cause of death.   Caleb, nicknamed “Killa K” or “Double K,” was an infrequent, yet much-beloved character on the reality show alongside Tammy chronicling their constant battle with weight. In 2022, the two met at a rehab facility in Ohio, where they underwent treatment for obesity and they tied …