Your hus has to be in US in order to submit I485, otherwise, he has to go through consulate processing. He can submit I-485 if he is in US when you actually did submisiion, but later he needs mostly in US (definetely can travel to Canada). After GC, he has to stay in US more than 183 days each year.
US and Canada is a little tricky as sometime it is like one country, but you have to take your own risk as each government can contact the other pretty easy.