Looks like Wwendy has you covered :)
1-2 tsp per gallon, pre-dissolve it prior to adding in your guy, use water conditioner. Daily 100% water changes. Should only be a few days.. you can use a qt tank or a small soap-free tupperware to float in his home tank to keep him warm.
If you use a smaller container then a gal, you can use an empty water gallon jug to mix everything in to use for the daily water changes.
Epsom is safe to use for as long as needed, past the 10 days- the 10 days rule apply to AQ salt. But for SBD/bloating it should only take within a week to fix.. you can remove him the day after you see him swimming correctly.
Good luck, keep us updated.