Oh Ali, that's bad news but perhaps all is not lost.
I would suggest going for the medical waiver. Have a read through this previous post about
medical waivers .
I would say though, I know they take exception to overweight people, but don't necessarily fail them. Usually it just means an extra batch of tests for possible complaints that overweight people tend to suffer from. If his high blood pressure is well controlled by medication alone, there really shouldn't be a problem.
You're a nurse and NZ desperately wants you there, so I would think that would go well in your favour if you have to go for a medical waiver. It would be nice to think that INZ wants you enough to overlook his weight and controlled medical problem.
Good luck with the Case Officer. I hope she can confirm what I've said and all will be well in the end.