Given that John's continued presence will enable Elly's inertia and need to not engage the outside world, she'll feel somewhat conflicted about this but mostly think that she did all she could. Also, John's inability to admit error will silence the voice in her head that agrees with the Martian and wishes that her daughter had spoken up sooner.
After John passes on and Elly can no longer rely on his idiocy to validate her refusal to face her doubts head on, the realization that she didn't do near enough for her father or the woman who, despite talking a good game about being a better nursemaid than people with skills and training, was clearly out of her depth will be allowed to be how she views her past. The means by which this will change will most likely involve having to cope with the needs of her father's namesake during the collapse of the Lizthony marriage.
What the need to look out for the grandson she sort of thought would help Liz get her priorities straight will do without John to keep her on the path of self-righteous self-absorption is to finally get her to admit that she never had any priorities worthy of the name because she lacked self-awareness. In the hands of a good writer, she might even be okay with this. Who knows? She might even admit that she never really understood how damaging her self-pity was to her children and that she pressured them into becoming things that they shouldn't be just to make herself feel good.