One point - don't keep him in a bare, empty QT tank. It's very stressful for fish to be in a bare tank, and won't help him recover, battle off infection, or want to eat if he feels exposed and stressed. Use a black rubbish bag to tape on as a background even, that's a cheap temporary background and means he won't feel open on all sides. Add some plant matter - take some trimmings from your main tank that you don't mind throwing away after, more Indian Almond leaves, some floating plant, some fake decor you have tucked away in the cupboard and is easily cleaned and decontaminated - make it suitable for the fish, not what's easiest to clean.
If you're going to use meds, stick to the directions rather than adding your own rest days. If you're going to discontinue one and try another, large water changes and running some carbon to remove all of the old med before trying the next is essential. Give him a few rest days between the two medications if possible, and try other things to tempt his appetite. Once he's not in a bare tank, hopefully he'll have more of an appetite. Try collecting some life food, like mosquito larvae from a bucket outside, or get some from a starter culture or store, or put the word out to local hobbyists and see if they can spare some from their own cultures. If anything can get a fish to eat, live food is usually it. I got some live blood worms from a bucket outside that I'd been getting some mozzie larvae from the other day. Agree with
@Alice B that garlic is also often used since fish seem to be more likely to eat with the garlic scented stuff. There are recipes out there for how to scent food with garlic yourself. I haven't yet done it personally, so can't suggest a method I'm afraid.
As I say, I'm not that familiar with angelfish, never had them myself - but have had a lot of experience with other animals, like trying to save waifs and strays, and runts. I seem to have a knack for it. But...
If the eyes are an indication of a potential runt, and
@anewbie suspects it may be an internal blockage... I'll give a word of warning not to get your hopes too high. Fish like angels are prone to having some phyical issues, right? Breeders having to cull heavily due to deformities/fin problems etc? If there are a lot of external issues, then there are just as likely to be a lot of internal issues, ones that may be preventing him from wanting or being able to eat. There's no way for us to be able to tell without a necropsy. So while I'd also be continuing to try to treatment at this stage, I'd just caution you not to get your hopes too high and try to aim any treatment to a likely suspect, rather than spending a fortune on different medications and hoping for the best. That if it's a runt with some internal, failure to thrive issue, that you may be throwing good money after bad.
I'd try sending this to the people at Wet Web Media, see what they say.