Awww...Poor Victor :( Sorry to hear he has dropsy. :-( I'd probably euthanize also if it was my fishy. With dropsy being so fatal it would be hard for me to let it suffer.
You can try Fungus Eliminator by Jungle. Do a full water change first if you can and then add the medication. Change water every third day and then add a new dose. I'm just learning about aquarium salt in with bettas and this might not be a bad idea either. 1 teaspon to 2 1/2 gallons. Good...