  We prove that the bulk eigenvectors of sparse random matrices, i.e. the
adjacency matrices of Erd\H{o}s-R\'enyi graphs or random regular graphs, are
asymptotically jointly normal, provided the averaged degree increases with the
size of the graphs. Our methodology follows [6] by analyzing the eigenvector
flow under Dyson Brownian motion, combining with an isotropic local law for
Green's function. As an auxiliary result, we prove that for the eigenvector
flow of Dyson Brownian motion with general initial data, the eigenvectors are
asymptotically jointly normal in the direction $q$ after time $\eta_*\ll t\ll
r$, if in a window of size $r$, the initial density of states is bounded below
and above down to the scale $\eta_*$, and the initial eigenvectors are
delocalized in the direction $q$ down to the scale $\eta_*$.
