Wow...lots to unpack here.
1) If the son was old enough to play AD&D, that must put him, at minimum, right around 30. So he's an adult, and this is about an adult father-son relationship, so the power dynamic issues aren't as much at play here. (If the son is actually much younger and still financially dependent on his father, that puts a different spin on things.)
2) The fact that the father is the only one left in the 4e group, and the son continues to want to run the game despite evidence he's the only one interested makes me a little concerned. At the very least, it looks like he has a strong tendency towards system mastery as his primary game motivation (especially considering the details like he reads the books cover to cover to remember all the information). Trying to keep playing a game that's descended down to 1 player also suggests some difficulty either reading or accepting social cues.
3) Hiding books and replacing them with new ones suggests that the inability to process social cues correctly might just have a genetic basis.

If you're 50+ and your son is 30+, you should be able to have a conversation like "Look, I'm not a big fan of 4e anymore, and I'm the only one still playing. I respect that you like the system, but I'm just not interested in playing anymore. Why don't we take a crack at playing 5e with your sister's group instead?" If having a frank conversation with another adult about your needs and expectations causes arguments and hurt feelings instead of a rational, respectful discussion, that's really something to bring to a therapist, not a D&D message board. Because, honestly, this isn't an issue about D&D, it's about setting boundaries in a relationship with your adult children.