((((((((((Amber))))))))).
Words fail as wakes cross.
I am glad you know about self-protection.
And shoring up Hol's understanding of the same may work, if it's one statement you've never made to her before. But if it's just a repeat that might be a sign from life that Hol has to figure out what co-dependency is on her own. You COULD send her a good reliable book about it, to relieve yourself of being the authority. (Just in case you slide down the slope I lived on -- fixing, advising, controlling, panicking, rinse and repeat....). Which wound up being toxic to us both.
One pragmatic thought. I got to a place where when financial help was needed for health issues, I made it my policy to mail the check made out to the provider, either as an exact amount or as a kind of "retainer" (for example, to cover therapy).
This allows one to know: 1) If the provider cashed it (which would indicate services used), and 2) When.
Leaves you somewhat in the loop, anyway. And you can detour around your D's untrustworthy patterns without insult or offense, simply in an accounting kinda way.
You're probably already doing that, but fwiw.
So much support to you and Hols and A--and her children--
love,
Hops