I think that had the OP included more of what’s in post #43 in the actual post #1 we’d have had a more successful thread. As it is, a lot of us projected our preconceived (hah) notions onto what little meat was in post #1. Not so good.
IMO his relationship with the woman is pretty deep and long-standing. IOW, he’s got a pretty good insight into her long term values & behaviors. ISTM that she’s demonstrating “baby fever”. She wants one in the worst way, and nothing else much matters. It’s a fixation. And to the degree that’s an accurate assessment, our OP is properly concerned. For her, for the child, and for his longstanding role as her support system.
GrumpyBunny’s glib advice to butt out & write off the relationship at the first sign of backlash hardly seems like a caring and charitable approach. And she wasn’t alone in suggesting it.
What any of us owe our IRL friends is our honest and considered opinion, diplomatically delivered. Heck, that’s even what SDMB is really all about.
My take: It’s not the OP’s place to say she *can’t *have a kid. It *may *be his place to say that in his opinion it’s not a good idea.
Further, if we correctly understand that she tried to shanghai two random guys into being unwitting sperm donors, she needs to get an earful about that immoral and perhaps even illegal behavior. That may be the lever to get her to see that she’s losing perspective on this and the desire for a kid is transitioning from healthy desire to unhealthy obsession. At a minimum it needs to be part of steering her to the safe and aboveboard option of getting sperm from a bank.
Finally, the OP himself can also lighten himself up about this. The absolute worst that happens is an aging psycho bitch pickles off an autism spectrum kid & raises him/her to be neurotic & miserable. Just one more face among the few hundred thousand similar kids to be born in 2016. Not desirable, but not the end of our, your, or their world either.
Conversely, the absolute best is she gets over “baby fever”, gets a proper sperm-bank donation, births a healthy kid, turns into a fine mother and raises him/her in a loving way including the OP & the other interesting families to appropriate degrees. The kid ends up well-adjusted and happy.
Which will it be? Heck if any of us know. If only the best potential parents in only the best circumstances had kids, the world population right now would be a few hundred thousand, tops. Not 7 billion. Humanity muddles through somehow. She will too. Relax.