Understood. You are going to want to complete water changes to eliminate the salinity before starting the meds.
Just add the freshwater back into the tank SLOWLY, and the fish will be fine adjusting to the salinity drop...
I'd suggest doing a 50% water change, and refilling it with temp matched (as best you can) dechlorinated water, and take an hour or two to completely refill the water.... Do it in short additions. If you can attach a hose to your faucet and run that at a trickle into your tank, that would be better. If not, then just slowly adding the new water in will do it fine.
Thank you so much for all your advice, I am greatly appreciative of it! I am hoping the fluke solve will be dispatched today as its coming first class so should be here in a day or two, so I should have that time to return the water to normal again...
So do I do a 50% water change today and again tomorrow to lower the salinity or is one 50% change enough?