Figuring out the due date

[bittersweeet]

My brothers baby was 'due' on the 24 of November, they've been in hospital for 4 days already, he's now 7 days over due and it doesn't look it he's gunna be here anytime soon, the thing that confuses me is that they didn't really know when they baby was due🤔 we originally got told he was due somewhere between the 14th of November and the 27th,mow it's the 24th....

My brother said something to me yesterday about him not thinking he's due until the 24th of this month which means he'll be a 3 weeks early,
I guess my question is how do they really not know when they due date is?, surely hospital staff and the midwives would know?

They know when they scan baby. They take measurements from head to rump and figure out how far you are based on its size.

@TokenGinger see this is what I said, but they are admitted they don't know the date, something doesn't seem right