Have Bird Questions? Ask a Bird Specialist.
HI, this is DRB and I would be happy to help you. Unfortunately, the life span of cockatiel's in captivity is usually only 20 years maximum. So,your little guy has lived a long time which is great. When birds go to the bottom of their cage,they usually do not recover. That is usually what they do when they are close to dying. Unfortunately, the only thing you can do is to take him to a vet and have him put down or let nature take its course.I prefer euthanasia because then there is no suffering......
I am very sorry to hear of your troubles with your little guy, they become such a part of our families. Please let me know if there is anything else I can do even if it is in just providing emotional support. Most Sincerely, DRB