The thing is that as awful as it was, maybe I personally got through it initially without doing all the grieving, because I thought so much of my grieving had happened after she was diagnosed with such an awful, bleak thing.
In reality I was still dealing with it ten, fifteen years later. Because pre-death grief and post-death grief are different things.
This only really came home to me three and a half years ago when my (elderly) father died after years of moderate dementia; this hit me so hard and continues to weigh on me, and I realised I'd tried to avoid grief when my mother died. I miss my father in a way I never allowed myself to miss my mother, and he had the good long life.
Grief is there whether you want to acknowledge it or not.