I appreciate this story but at the same time, I felt sad reading this.
Your friend is 24 and living in London, and most likely has a job. I'm sorry but your friend isn't a 16 year old, but 24 is a grown adult. In the 90s, 24 was the average age to have children and get married. Plus, the UK is pretty generous to new parents and they give out handouts to look after the financial wellbeing of families. I'm pretty sure your friend and his girlfriend are well paid professionals , am I right ? So what was actually holding them back?
You post those probability figures but maybe its worth remembering if the probability of her falling pregnant was incredibly miniscule yet became pregnant , maybe that's a strong message from God?