Yes you definitely can move him into the garage. If it doesn’t have windows I would leave a light on during the daylight hours and turn it off when dark. He may or may not hibernate so you will need to keep feeding.
I think you may need to cut down how much you’re feeding him though as over 500gms in 2 months is quite a big weight gain. No more than a handful a day and only in the evenings
I would not release as he won’t know where to find food – most of his natural food will not be around yet, and if it freezes he’ll struggle to dig up worms etc. He also won’t be able to build a dry nest at this time of year. So I would not recommend release until spring when the wild hogs start getting up.
Hope that helps