He hadn't met the groom but was expected to fly halfway round the world to play a bit part on TV in front of millions for the biggest performance of her career?
Yes, because that is what parents should do. Keep your mouth shut and smile at the wedding. Obvs things were different as he was ill. But if he didnt answer the phone to her, that is awful.
I am not defending their behaviour since, such an entitled couple. But in this, I think they tried.