@bettyboop it all depends if the visa granted to him has no further stay restriction. Be mindful that if you guys are doing this pathway in the view of eventually migrating to Australia, this isn't a guaranteed approach. This is a current issue now due to recent changes and marami who are on employer sponsorship are stuck right now dahil wala sila option but to leave Australia when their visas expire. This type of visa can no longer lead to a permanent visa anymore. If I were you, it's safer to get there on a GSM visa while nasa occupation list pa yung chef. Also, though perhaps the advice you were given might work in terms of transitioning to bridging visa then 485, be aware that no one, not even an agent can guarantee the timeline of visa processing and if sakali tumagal yung process, your husband will not have work rights while on bridging visa. The question is, who will finance his cost of living whilst waiting? I hope this was explained by your agent.
Unfortunately, I am not a fan of utilising 457 visa as an option pathway to migration because it usually isn't the best one for aspiring migrants. Same as student visa, though I'm a living example that it could work, it's also not a guaranteed pathway.