Okay, So you are saying that there were no other fish in the tank with the Angels. Correct?
At this point, the fact that the fish were doing better in the R/O water at the boyfriend's, I would wait and see how they react to the switch to your main water. If, under his conditions, the fish handle the water change and continue to do well, I would consider stripping down your tank, sterilizing everything and restarting from scratch rather than blindly medicating. I would still advise that you acclimate them back to the tank and to do it as I layed out and not the way you did it before.
IF the fish do not respond well to the water change, you need to consider changing water to the r/o as there is obviously something in your water system that does not agree with the fish.
That's my best advice for now for the main tank.
As for the fish in QT, if they start to deteriorate as the others did, I suggest you get them either over to the BF's or get some of his water to use in your QT tanks as this seems, at the moment, to be the magic elixer.
Medicating should be the last resort not the first. Proper conditions tend to prevent the need for meds.
Keep me posted