As I understood it, if you need a job offer to gain enough points to submit an application and that application is successful, then you would be tied to the NZ employer that offered you the job for 3 months. After that you would be free to go after any job you wished. However, when I read
this it talks about sustainable employment for 12 months or more if you're claiming points for it. Somehow this doesn't seem right - for this set of circumstances, anyway - as I've often heard about people changing jobs not that long after they've been in NZ. The INZ Operations Manual is very ambiguous and doesn't always compartmentalise it's categories so you know what is relevant to what.
This tells you about
work experience . Check me, but I can't see anything that gives a timit limit for when previous work experience can be counted so I wonder if he could get in with his mechanical engineering quals, if that's what he'd prefer.
My brain is on the blink at the moment - information overload - wading through different pages on the user-unfriendly Operations Manual, so perhaps you could have a read through
this which concerns relevance of qualification(s) and work experience to employment. See if you can come up with any answers. If not, come back and I'll have another look. Perhaps someone else will be able to sift through this and come up with an idea of what is best for your partner to do.