For fella.
The bubbles in the eye would be an indication of Mycoplasma G.
You may want to try increasing your Tylan50 dosage a little bit. How much does he weigh?
The Terramycin would be best since it is an antibiotic ointment for the eyes, where the Microcyn is antibiotic free, but it may be helpful and soothing to, so use it. All of that stuff is $$.
Try to keep him going. I'm sorry he is not responding to the meds.