Stranger Things Season 2: 9 Crazy Fan Theories (That Might Actually Be True)
7. Eleven's Mother Is Linked To Her
Sticking on the topic of parental figures, and one who actually is related to Eleven, there is speculation that there's more going on with Terry Ives than presented in the show.
Terry is, if you recall, the biological mother of Eleven, who was experimented on by Dr Brenner while (unbeknownst to her) pregnant with Jane/El. Brenner took the baby away, and covered it up as a miscarriage, and a few years later Terry suddenly entered a catatonic state.
One theory is that she's linked to Eleven, and her mental state is intrinsically connected to Eleven being in the Upside Down, with improvements when she's closer by. Another notion is that she was actually poisoned by Brenner - with the 'sister' one of his assistants - in order to throw Hopper and Joyce off the trail.