Epsom salts should help if he is retaining water though. Regular salt makes a fish retain more water, but epsom salts help to relieve water retention (thus why it is good for dropsy because these fish also retain water).
In all honesty, if you think he's got fluid build up... I'd try the espom salt baths. Two a day for 15 minutes each time. I would try this for 4 days, if no improvement stop. No need to stress him out more. However if you see improvements (even a slight one) then consider continuing treatment.