I was in the exact situation with DD1. DH was working in Kal and my DD fell smack bang in the middle of his week home... I ended up going 8 days over, and booked a flight for him at 1.30am so he could get on the morning flight out. Had he not made that flight, he wouldn't have been there.
MIL was with me, so there was *someone* there, which was great.

Essentially though, the only thing you can do is hope for the best, plan for the worst. If you KNOW that you are going no more than 5 days over, and he will be here for your DD anyway, then I would run with hope, and make sure his employers know that if bubs hasn't arrived and you are being induced, DH won't be returning to work.
So if I were in your shoes (again! lol) I would leave his roster as is, the chances are you will go over anyway.

Remember too that he is entitled to other leave besides AL when baby is born - he can claim some Parental Leave (not through CL but as a standard entitlement like Bereavement Leave) it isn't much, and it is unpaid, but he is entitled to it nonetheless.

Good luck!