to answer your question: yes, he can easily get a job with the NET scheme. they are desperate for teachers as they are trying to get one NET teacher in every schooL (some schools share their NETs with another school).
as for his wife getting a job permit, that is a bit tougher, usually to get a job permit you have to get a job arranged prior to arrival in HK. it's a major sticking point with couples where 1 spouse is employed in the NET scheme but the other can't get a work visa in HK. it may change in the future though.
have your friend check out my website:
www.maskofchina.com/hk
or contact me for details on the interview process...
good luck!