Dissociation processes in three-dimensional He+H-2 collisions are studied by using a semiclassical approach which treats the relative radial motion in classical mechanics and the other motions (vibration/dissociation and rotation) in quantum mechanics. Centrifugal sudden approximation is assumed to solve the semiclassical equation. The results are compared with previous full quantum mechanical calculations in which infinite order sudden approximation has been applied. The present study shows that the molecular rotation must be accurately taken into account in the dissociation process even at very high collision energies where the energy sudden assumption is usually expected to be satisfied for low molecular rotational states.