Okay Ben. Thanks for the extra information. Actually, you have several Avian vets within your reach. You have one just a little NE of you,as follows:
Southwest Florida Veterinary Services is located at 12288 CR 769 (Kings Highway) in Lake Suzy, Florida, near the Desoto/Charlotte County line.
And here is a link that will show other Florida Avian vets, a few of which are fairly close to you including Nokomis and Englewood, just up the road. Click here: Exotic Bird Society of America Florida Avian Veterinarians
I'm afraid you bird is going to need one. Based on your description of symptoms and the other information, there are two suspects that come to the top of my list. The most critical of them is a possible exposure to something toxic in the home where he flies, and/or either lead or zinc poisoning from an unsafe metal either in his cage or toys or both. It's only been relatively recent that it was discovered just how very at risk our birds are if they have access to metals containing lead or zinc. Most older cages and toys had both. Another problem he may have is diet related. It sounds as if he has been on a mostly seed diet all his life. That has left him at risk of fatty liver disease, fatty tumors, (which could be pressing on nerves and blood supply to his legs) and obesity. A birds diet should not be more than about 25% seeds and seed products. They need fruits, veggies, green leafy items and much more. He might also be suffering from Avian Gout. Obviously I can neither diagnose nor prescribe for you in this format. All I can do for you is give you my best guess as to the possible problems, based on the information provided. I strongly urge you to get in touch with one of these vets and get him in asap. First thing tomorrow would be great. In the meantime, don't let him get chilled. Keep him as quiet and stress free as possible. You need to either remove the cage grate and line the floor, or line the grate with several layers of newspaper. Don't allow him to get a foot or leg down through the bars and maybe end up with a broken toe or leg. Put sturdy small dishes he can't tip over on the floor so he can get to them for food and water. If you put several layers, it will be soft for him and all you have to do is peel off the top layer as he soils it. You can cover the top and three sides of his cage to help him stay warm. The closer we can keep an ill or injured bird to 80F, the better. I'm so sorry there is no home remedy or cure I can give you for this situation but I hope this information will be helpful and that you can get him in tomorrow. If you need anything else or have more questions, just let me know. Patricia