In a recent paper [AIMS Materials Science 4, 1052 (2017)], Elena Díaz et al. have considered the coherent electron dynamics in the electric field created by the helical arrangement of dipoles of the molecule backbone, giving rise to an effective spin-orbit coupling. They calculate the spin projection onto the helical axis as a figure of merit for the assessment of the spin dynamics in a very long helical molecule. They prove that the spin projection reaches a steady state regime after a short transient. They compare its asymptotic value for different initial conditions, aiming to better understand the origin of the spin selectivity found in experiments.