So he suspects SIBO ... has he run any tests, like a basic breath test, which would measure the concentration of hydrogen and methane in your exhalation?
If nothing he's tried on you so far has worked, is it possible that you're not, in fact, dealing with SIBO?
The symptoms of SIBO (poor or no appetite, abdominal pain, nausea, bloating, extreme sense of fullness after eating anything, unintended weight loss, etc) are diffuse and can be indications of any number of other things. What does a differential diagnosis rule either in or out? Has he done one and discussed it with you, or is he just throwing shite at the wall to see what sticks?
If what he was recommending was just another ABX, it might be worth the gamble, but cipro is anything but .... if you haven't Googled the side effects yet, it might e a good idea to take a peak ....this is serious stuff and should probably be reserved for life or death situations where taking a gamble of that size and weight might be warranted ....
He's tried multiple ABX on you, one of them used mostly for tooth infections, and these alone cold cause an overgrowth of bad bacteria after killig off most or all of your good bacteria. It's possible that he's willing to risk your well-being by using this nuclear ABX response to cover his own posterior.
It's your body and no one can decide for you, but it might be a good idea to get more info, which hopefully can be provided by the more expert voices on this site ....