Here are some reasons to think that Youzi did not regard family as the root of humanity or of the Way. (I used to think he did.)
Most of my argument focuses on defending a view held by Soothill, Leys, Chin, and maybe Lau and Slingerland: that by 弟 in Analects 1.2, Youzi meant elder-respect, a virtue commonly associated specifically with life outside the family. It would follow that according to 1.2, only one of the two parts of the root of humanity is specifically a family virtue. If 孝 and 弟 have something relevantly in common for Youzi, family isn’t it.