I am the codependent mother. Or I was.
I absolutely have damaged my children and will spend a long time trying to heal that. It makes me so sad.
I think the reality is with the elderly the likelihood of them realizing any of this and actually changing their ways is next to none. The only thing left to do is to keep your own boundaries and not engage in it.
Give yourself a break. It's hard. Try not to focus on only that, and maybe make plans so you are both relatively busy for the visit.
Big hugs.