Visa/Job

Need advice please. I am a Permanent Resident of HK, and have the HKID. My husband, British, and would like to work in HK [as temporary teacher, he's qualified teacher in the UK and got TESOL cert]. Suppoingly , it should be wasy; but I work in the UK [rather than HK]. Anyone knows if that will be a problem if the sponsor for the dependant visa actually live and work outside of HK ? For the stay in HK, he and my son [born in UK] will be stay with my parents. Will that be good reason enough [like let the little boy have more time with his grand parents - they both disable, not able really to fly to UK to visit us] for getting my husband a dependant visa ?

Many thanks