Hey BethRags,
I used to have a ''friend'' who sounds somewhat like the second friend you describe. She was on and off meds, (rinse and repeat), had a severe mental illness, would not stick to therapy although it was offered, and I finally realised that she was ''on transmit only''.... I spent hours (for years) listening to her and giving support, comfort and thought out advice. I did not tell her how I was ''getting on''.. Eventually, after years, she stopped phoning me. Maybe she found another friend to dump on?

Sometimes the needy people come in other disguises, like the person who always has to be ''right'' and judging others, passive aggressive, feels superior yet is deeply insecure, violating known (and obvious) boundaries repeatedly, sneaky and requiring endless significance (endless attention) This is similar to my Paternal Unit also Sometimes I am tempted to show that person my teeth (not anyone here)

I wonder why we both have these people in our lives (or have had them)

Boundaries. I'm working on these too.