Can you describe exactly what the body language is? there is a difference between defensive or aggressive behavior sometimes people cannot identify the two. Curving the body and gaping whiping the tail is defensive... A bite would be its last defense resort.. And well simply charging is obvious aggression.
Any other changes? color, diet etc? Iguanas are known to like certain people but not others little things like colors people wear, their scent, if they are submissive to the iguanas move or quite dominant I could probably write a long book that discusses iguana mood swings.. Any changes you know feel free to share here for better idea what is going on.
This time of year he could be going through mating season.. In which case he is a hormonal maniac and wants to breed. They will do this for 1 or 2 times a year and it can last a few weeks or even a few months at the extreme. I've seen a few cases where males can have a hormone imbalance that can or sometimes cannot be fixed with vet expertise.. It all depends on what is causing it. If you have not experienced breeding season before you've had one mellow ass iguana on your hands. Are you completely positive its male? Oh to add to this.. Iguanas tend to get quite aggressive if they are ill so I wouldnt rule out a vet visit.
For the moment I would not allow your iguana around kids or other animals. No free roaming until your iguana returns to "normal" - but even then they can surprise people completely off gaurd. Iguana bites can be very severe leading to permanent scars and in some cases bone and ligament/tendon damage depending on where the bite hits. Their teeth may be small consider them shark teeth.. Their jaws are incredibly powerful and will rip right through flesh. IF the iguana locks on anyone DO NOT fight it and rip it off.. That will cause a lot more problems... Thats the first thing that people will try to do because it simply hurts like a b###h. Instead try to find like a bleach or ammonia wipe and wave it in front of its nose obviously dont put the chemical on the reptile itself.. Try making it go upside down.. Can even soak it underwater in the tub. I traveled to a hospital years ago reptile attached to the back of my leg and all when it latched onto me.