Soft of a proxy thing

[Preamble]

I am having big problems with a personality disordered parent, but not mine.  That's in the past.
The parent bothering me is my child's who is intellectually disabled and over 30. When I
try to help my child, the parent swoops in and destroys it, but my child naturally does not have what
it takes to: change their name, refuse contact, keep things quiet, or choose good friends.

I tell myself that even if the other parent was gone, my child would still get involved with the same
type of person.  But that new person would not know "all about them" and "all about their family".
I'm miserable and very confused about this situation and it doesn't seem to fit anywhere.

[Liketheducks]

I'm so sorry you're here.   I wish I had some advice to give.    Unfortunately, you have absolutely no control over the parent's actions...or your adult child's.   It would be completely natural to feel frustrated and hopeless over the other parent undermining your efforts.