Well curing "monsterism" and "corruption" are different I doubt putting a helmet on claire would reverse her current state, wanting to go from superhuman to human could be "regressive" but just making sure peoples powers dont mutate in harmful ways (nyx/henri) should be something viewed as beneficial. We also know that becoming a monster/human causes biological changes but corruption is seemingly mental/mystical (nyx got mind raped by "ghosts" for a time/being able to "hear monster whispers at night") so "corruption" should be much harder to cure.
As the person above me says since he recalls the guy who told him "your life aint that shit kid" he would have to remember Ella, the only way for her to know him without him knowing her is too meet before him mom died.
Well we "know" Stephen meets syla, stephen likes her tiddies, stephen too horny to care about her shapeshifting/clearly being mentally messed up, stephen marries her (all confirmed in dream?) from here right now my guess would be: stephen gets job while syla is being "treated", syla lies to him about the treatments, MC is born and probably does some monster stuff or whatever ended him at same place, stephen learns whats going on and does some blackmail stuff to get mc/syla out of there but syla dies in order for mc to live/the lab sends someone to kill her.
I dont think stephen would give MC willingly for experimentation, he sure as shit wouldnt willingly give up syla for it, and that goes double when you consider how "above and beyond" tanos would likely go (like he did with amber/liz)
Considering cole is "angry" but otherwise "sane/functioning" I dont think it was "just" tanos experiments that are the reason, I think the real reason has more to do with whatever "bad stuff syla took in over the years" that caused her a "true spawn" to no longer be consdiered "pure"......beyond that would be rampant speculation but my money is on a certain raven and their lord