Copper is only a treatment for Ich, it will not only not help with the Popeye it will weaken the fish as the Copper is toxic, just to a lesser degree on fish than Ich. I do not recommend it's use here.
I would quarantine and treat with antibiotics if you have them. When I had eye infections in my clown pair I was able to successfully treat them with Metroplex and Kanaplex. My fish had more cloudy eye however, not Popeye.
Hopefully others with more experience with Popeye than I will chime in.
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