Xiao He has no descendants. Why is Liang Wudi a descendant of Xiao He?

Xiao He is indeed the ancestor of Liang Wudi. Xiao Daocheng (427-482) was the first emperor of the Southern Qi Dynasty and the grandson of Xiao He XXIV, the prime minister of the Western Han Dynasty. His ancestral home was Lanling County, Donghai County (now Lanling County, Shandong Province), and he was in office from 479 to 482. Xiao Shunzhi, the father of Liang Wudi Xiao Yan, and Xiao Daocheng, the founding emperor of the Southern Qi Dynasty, are cousins of the same great-grandfather. That is to say, Gao Qi Emperor Xiao Daocheng and Xiao Yan's uncle and nephew in Liang Wudi are contemporaries. Xiao Yan is Xiao He's 25th grandson.