Thank you for all of your responses, albeit some are a little argumentative.
I stayed for another week, and enjoyed every second of it. I spent so much time with my toddler grandson that I’ll remember those precious moments forever. My new granddaughter is precious and meeting her within 24 hours is something I’ll treasure.
My DS & DIL had originally asked me & my DH to book into an Airbnb before the birth (which we did & actually enjoyed) but were desperate for me to stay with them once my GD was born. This worked out well for all of us. They both realised they needed my help & it really brought us much closer as a family.
My DH & my DD at home finally accepted that I would be staying longer than expected, despite complaining. The lack of a car for my husband was an issue, as we live in a fairly remote area, but he dealt with it.
In hindsight, my DH realised that he was being a bit selfish, realising he didn’t even manage to meet our GD. On my return home he was super supportive. We’re going back to see our family in a few weeks, where he’ll get the chance to meet his GD.