It does wear off quickly. Maybe it would be more accurate in retrospect to say, it was a shock. An OMG or holy fuck moment.
No, I am not a rabid royalist as I have been accused. To me bad news is a shock. Like when George Michael died, or Freddie Mercury.
The Queen was dedicated to her role. I think Charles knew and understood that. She made a promise to the nation and was determined to be a woman of her word. It would have been so much easier I am sure for her to disappear off into the sunset and see her grandchildren and great-grandchildren and spend time out in nature with her horses and dogs.
She was neither cruel nor selfish. She believed it was her responsibility to rule until she died. She was selfless rather. She could have chosen to make her life easier and more enjoyable, especially when she became ill but her principles did not allow her to do that. I think she was admirable. She was sharp right until the end, as Boris Johnson said of her two days before her death.
I think she and Charles had a very loving relationship in later life. It seems it was difficult for him as a child because his parents were remote and away a lot. However it appears the whole family became closer as a whole as they all got older.