There's no timeline for grief
Whereas there is no set time for how long grieving should last, if you feel that it has been going on too long for you it would be advisable to discuss it with a therapist.
I'm not sure "should" is a factor. People mourn for as long as they need to. Some can work through grief in a relatively short time; others are just never the same.
Forever. The intensity is what lessens.
Its a lifetime memory but one needs to let go and move on, how long it depends on the person
Can't set a timeline for that.