really? i didn't know that about aquaruim salt and dropsy. but, it doesn't sound like they've got dropsy. i've never really had to deal with SBD, and never actually understood how to treat it. o.0 when any of my bettas(mainly my VT, Cup) get bloated, i just fast them and they're fine the next day. >.>
aquarium salt is supposed to help de-stress bettas, and i use it often with a sick fish, or if one of my boys or girls has ripped fins. not only does it keep things clean, but it relaxes them(i swear they do seem happier with a bit in their water).
either way, i do hope they get better.
as a side note, if you're low on cash but wanna get decent-sized tanks for them both, most pet stores carry Kritter Keepers, or whatever brand you have, in the rodent section. you can get one that's around 2 gallons or so for about $10 or so. :d