I remember grief. My father died when I was a teenager. Although he'd never been in robust health after the war, I'd no idea that he was going to die. He'd got up as usual to go to work, and had another, more serious heart attack. Nothing else mattered for some time afterwards. I couldn't understand how anyone could be laughing (even people who I didn't know) it all just seemed so wrong at the time. Anything could trigger tears.
When my mother died in her eighties, it was a very different sort of feeling, I knew she was ready, her quality of life was very poor etc. In some ways that grief was tinged with relief, and guilt. None of us knows how others deal with loss, its not a proscribed state or feeling. We can however allow those who are grieving to have their own feelings and to cope in their own way.