In my experience, grief is not something we “get over” by following pre-prescribed stages, but something we may be asked to tend to, as a part of making soul, throughout our lives. It is very individual and takes a unique expression for each person. The timeline for this is not given by the psychiatric community and insurance panels, but written in the stars. To pathologize the experience of grief is a work against nature.
The grief process may not have an endpoint, a goal line or state of completion in which we come to some final resolution, where we've "finished" and land in some untouchable place. The heart is endless and grief may be a companion for the duration of a life. For me it is not so much a process as a non-linear, unfolding partner. It moves not by way of straight line, but by that of circle and spiral.
Even if we no longer grieve the sense of a personal loss, we may be asked by forces larger than ourselves to grieve for the ancestors, the ones who have yet to come, and the earth and her fertility. At some point, perhaps we can no longer discern between our own grief and that of a galaxy being born and dying. Grieving is not only personal but cultural, historical, and archetypal. As it humbles and purifies, it opens a portal into the mystery.