My DH and I had only been together about a month when I found out I was pregnant. Had been on the pill but had been sick and stupid me didn't think. TBH he handled it a whole lot better than I did. Lots of support and encouragement, never a conversation that didn't revolve around what "we" were dealing with, an enormous flower arrangement delivered to me with an incredibly supportive card. I ended up having a m/c, but it had proved to me that this was a man who would stand beside me through it all.

IMO any man who turns around and issues ultimatums when HE got a woman pregnant needs to grow up, stop being so selfish and accept some responsibility. No, unplanned pregnancies are not always blessings in disguise, but a woman never gets there on her own. Even the ones that say they've been tricked and "trapped" after being told their partner was on the pill, there's always condoms to be extra sure.

I hope your sister is ok, and gets the support she needs. Sounds like she needs it from someone other than him though unfortunately.