  We investigate the regularity of elliptic equations in double divergence
form, with leading coefficients satisfying the Dini mean oscillation condition.
We prove that the solutions are differentiable on the zero level set and derive
a pointwise bound for the derivative. As an application, we establish global
pointwise estimates for the Green's function of second-order uniformly elliptic
operators in non-divergence form, considering Dini mean oscillation
coefficients in bounded $C^{1,1}$ domains.
