Your rooster brought back memories of a favorite roo I had many years ago. Penrod, a Buff Brahma. It was before I realized I had lymphoid leucosis in my flock. My rooster suddenly began to go lame. I thought it was an injury, but it kept getting worse. He quit eating and became weak. This was...
Try the penicillin. It's very close to amoxicillin. It depends on the bacteria if it's resistant to penicillin, though. You won't know until he's been on it for a few days if it appears to be working. In case he isn't showing improvement, a different antibiotic may be necessary.
Be aware that...
I agree with both of the posters above. You need to clean out his eye as accumulated pus is prolonging infection and that can cause him to go blind if it goes on too long. And he should be on a good broad spectrum antibiotic.
You will not pop his eye ball out by removing the pus. The eye ball...