Fall is approaching and many males are beginning to show signs of breeding season. This may or may not be the case but its always good to read what you can and prepare for the possibility of a very aggressive iggie for a couple months.
If its not breeding season there is still hope. Some Alpha males seem to hold grudges towards certain animals or humans.
My husband and I had an ig that hated me but accepted him quite well. I was unable to touch this iguana the last 4 years of its life with the exception of needing to take him to the vet or putting him outdoors for sunning. It was always a fiasco but the towel trick worked long enough to transport him safely.
He passed away last year from cancer and the only way we knew he was sick was because he began letting me approach and even pet. Not his norm.
We have another male that seems to actually sort of like me but has a strong opinion about my husband and would gladly chomp on him given the chance.
Weve spent years learning and loving them despite their obvious dislike for us. It was the promise we made when we took them in.
In addition to those too we have had many other igs and currently have 6, 4 of which are male.
Of these others ,they all seem easy going and do not favor one of us over the other. Perhaps they know that theres already an alpha male ig in the house? Just my theory, so much to still learn about these amazing creatures.
If I were in your situation, I would first read up on breeding season and see if that may be whats going on.If thats the case, all you can do is keep the ig and the himan safe from harm, feed and clean when hes out of the enclosure, offer a potential fake mate ..Ive seen igs take to stuffed animals, shoes, even a baseball glove or colorful blanket so you may have to try several things til he finds the right "girl" haha.
If it continues and is not season related, well the same rules apply because the behavior will be about the same.
You can try retraining. Handling at the same time each day ( I prefer mornings, before they have a chance to warm up and fully wake). Try to keep the same schedule, have the house quite , get him away from the cage where he cant see it so hes out of his comfort zone as they can be very protective of their cages.
Also be patient, it can take well over a year to get an iggie to tolerate you and it sounds like your guy has not had much handling and is going thru a lot of changes.