Justine, who apparently is almost certain to die here.
According to the family records, just over fifty percent either don’t survive the delivery or die shortly after.
That's not even close to almost certain. Given advances in medical care over the decades and likely centuries the family records go back, it's probably more likely than not that Justine will survive the pregnancy. A certain, or even large, percentage of that death was likely due to mundane causes, especially when combined with the mother's weakened state. From the 1700's through the invention of antibiotics, the mortality rate for mothers was 400-500 per 100,000 in Britain. Today in the U.S. it's 15 per 100,000.
Especially if she is on birth control, supposedly Thomas is "for intents, sterile," two weeks late for your cycle could mean a lot of things.
And my kind are all but infertile to boot.
All but infertile and for all intents and purposes sterile are not the same thing. For example, for all intents and purposes sterile could mean that one could conceive, but the pregnancy would end before any noticeable physiological effects. All but infertile means very nearly or all except. So either Thomas isn't infertile at all because he's an exception to the general rule, or all wamps are just very unlikely to impregnate a woman (or get pregnant for the females) in any given attempt. Eventually unlikely things happen given enough repetitions.
Also even with Molly's help, giving "birth" to her meant he'd live, not his almost certain death. So, no, not the same at all.
After Harry found out, Murphy said they'll "get that parasite out of your head." Harry responds that they "
can't kill the parasite. We
have to save it." Emphasis added. Also, without Molly, it did mean certain death for Harry. I'm not going to lay odds on what were the chances of Molly arriving in time because all we know is that she did. So outside of the slightly more likely to die than live probability being just unknown, it's exactly the same situation Justine is in. I think this shows that Harry wouldn't even consider abortion.
Exactly, Harry’s opinion as a mother is valid in this context, as a father not so much.
Harry has had experience in choosing between his True Love and his child, so he's got the exact experience Thomas needs.