C.S. Lewis wrote in his book, "A Grief Observed" the following paragraph:
I thought I could describe a state; make a map of sorrow. Sorrow, however, turns out to be not a state but a process. It needs not a map but a history, and if I don't stop writing that history at some quite arbitrary point, there's no reason that I should ever stop. There is something new to be chronicled every day. Grief is like a long valley, a winding valley where any bend may reveal a totally new landscape. As I've already noted, not every bend does. Sometimes the surprise is the opposite one; you are presented with exactly the same sort of country you thought you had left behind miles ago. That is when you wonder
whether the valley isn't a circular trench. But it isn't. There are partial recurrences, but the sequence doesn't repeat.
Like all of us do, Mr. Lewis was dealing with grief as best he knew how at the time. But there is one line which I wanted to look at a bit more: "Sorrow, however, turns out to be not a state but a process. It needs not a map but a history, and if I don't stop writing that history at some quite arbitrary point, there's no reason that I should ever stop." I think that's an interesting statement. Grief is an emotion that we have to actively stop at some point or it will continue until it consumes us. I would not try to tell anyone else how long it is right for them to mourn, but if they don't overcome grief and sorrow, at some point it will overcome them. No one would really want to be like the renowned Queen Victoria, who worn black the last 40 years of her life.