I think I agree with you. The story line shows what an entitled narcissist the 'Lois' character is - to be reacting to being called Jake by insulting his dying grandmother, saying she 'dead named' him. And then he stands up and is applauded for saying he has become a strong woman - his role-model being Lois Lane! It's not his Gran's death that upsets him, it's her denial of his gender ID!
Someone has a different agenda from the obvious one. That Gran did indeed pretend, even to labelling the photos, and said so when she was dying. She never had a grand-daughter, only a grandson. The message is that we all pretend that a TiM is a woman/girl, because it keeps the peace and thus we are using compelled speech. Alzheimer's freed Gran's tongue.
NB The script is better than 'Doctors' - though I remember the one episode I ever saw had the best explanation of why transgenderism is nonsense and how damaging it is that have seen for some while.