I would take it out and QT it for a few weeks. Keep water parameters pristine with constant (10% - 20% daily) pwc
's in the cycled QT. Larger pwc
's if the QT is not cycled. Reduce the salinity to 1.012 -1.015 in the QT tank over a couple of days.
The popeye should start to heal in about a week. If not, an anti-bacterial regimen would be inorder. You may want to do that anyway as both eyes being affected is not normally injury related as CaptaijnAhab already stated.
After the treatment get the SG
back up slowly. I would then capture the sweetlips to go in the QT for a week while the butterlfy gets comfortable in the tank. Then you can add the sweetlips back and see how things go.