  In a thin multidimensional layer we consider a second order differential
PT-symmetric operator. The operator is of rather general form and its
coefficients are arbitrary functions depending both on slow and fast variables.
The PT-symmetry of the operator is ensured by the boundary conditions of Robin
type with pure imaginary coefficient. In the work we determine the limiting
operator, prove the uniform resolvent convergence of the perturbed operator to
the limiting one, and derive the estimates for the rates of convergence. We
establish the convergence of the spectrum of perturbed operator to that of the
limiting one. For the perturbed eigenvalues converging to the limiting discrete
ones we prove that they are real and construct their complete asymptotic
expansions. We also obtain the complete asymptotic expansions for the
associated eigenfunctions.
