i don't know how to feel about my old ex

first off, i feel like i would be letting my emotions get the better of me if i said she wasn't a nice person.

back in 2022, i dated this girl alicja from poland. alicja has a childhood best friend, agnieszka. our relationship started off fine, alicja was very flirty, helped me whenever she could. she struggled a lot with mental health and i helped her.

here's the thing: if i wasn't immediately there at the moment, she would threaten to kill or harm herself. she also heard voices that weren't there some of the time.

if i didn't do exactly what she wanted, she would block me. at first, after our breakup, we were friends. then, she ghosted me and blocked me.

she happened to be friends with a friend of mine.

she then said she wanted to be friends with me, and ghosted and blocked me again. and she told me it was because she was autistic. whether that's true, i don't know, but yeah. agnieszka blocked me, too, unfriended me and all my friends, left all our group chats, etc.

what could be the reason for this behavior?