I had to learn this trick. I already had a YouTube acct I forgot about, but I uploaded the video from my phone to there. I had to send that video to myself through FB Messenger first as I couldn't figure out how to get to my YouTube acct on my phone as I use a computer. :old
Once I got it...
Amoxicillin can be purchased at aquarium fish pet stores in the form of aquarium treatment. It's called AquaMox or Fish Mox or maybe even other names. Dosage would be 250mg twice a day for a week to 10 days. I don't want to encourage you though if this is futile.
I thought so at first too but it appears to be way beyond a typical vent prolapse. You could try your idea but he'd have to be on antibiotics immediately to even hope to save him, and like @azygous said, it would be a slow and painful death.
I am so sorry you are dealing with this. I wish...