I'm concerned as well. It's important to note that once a cockatiel acts ill they're quite ill and in need of the attention of an avian-oriented vet (please see here: www.aav.org). This is a protective mechanism because sick birds are attacked by other birds in the wild. Angel's symptoms of claw deformity and lack of function, ocular disease, and being more quiet than usual are important symptoms but they're not pathognomonic (specifically indicative) of any one disorder.
The nerve supply to his foot may have been interrupted by trauma or neoplasia (cancer) anywhere along his leg/hip. He may suffer from a nutritional imbalance - a calcium deficiency, e.g. I can't envision the white spot but if you could upload a close-up pic of Angel's eye I'd be pleased to take a look. Can you upload a photo to our conversation? You can use the paperclip icon in the toolbar above your message box (if that icon is visible) or you can use an external app such as dropbox.com. I can be more accurate for you if I can see what you're seeing.
Nutritional imbalances are a common cause of illness in our pet birds. What has Angel's diet consisted of, please? Seeds should compose less than 20% of his diet. Ideally, a balanced pelleted diet such as can be found here: www.harrisonsbirdfoods.com or here: www.lafeber.com/pet-birds should be fed as well as hard boiled egg yolk, pancakes and cornbread, the tops of fresh greens, dairy products such as yogurt and cheese, fresh fruits such as apples, pears, melon, kiwi, and berries, vegetables such as broccoli, carrots, beets, asparagus, cabbage, sweet potato, and squash, and even tiny pieces of meat.
Please respond with additional information and further questions or concerns if you wish.