She may be cyanotic if the beak itself looks grey. This could be from a respiratory problem, shock, infection, or reproductive side effects.
Move the bird to an aquarium, box or carrier with soft towels in the bottom, no perch, and food and water in low bowls that he can reach easily. Put the whole thing on a heating pad on low or medium. Keep him partially covered, warm and quiet.
Do not try to force food or water. You can offer warm cooked rice, pancakes, cornbread, grapes, melon, greens in addition to normal food. Transport as soon as possible.
Pet/feed store medications and home remedies are harmful, ineffective, immuno-suppressive, and make them much worse and may interfere with the veterinarian's diagnosis and treatment. Do not use them.
She is very ill. She needs to see an avian-experienced
veterinarian ASAP for complete examination, diagnosis and appropriate treatment. Check the link http://www.aav.org/association/index.php?content=activeMembersList
for members of AAV in your area or call your regular vet and see who they recommend; ask if they really have worked with birds a lot. If she were my patient, I would start with complete fecal analysis and direct smear, for multiple parasites; bacterial culture and sensitivity of the feces and choana. Depending on the case I might do a fungal culture. Routine blood work is necessary to rule out other issues. Generally I start them out on antibiotics as indicated by the tests (I use a lot of human antibiotics that are injectable).
She may need injectable antibiotics calcium, oxygen and many other medications. Act quickly and good luck.
Birds should be on a high-quality, preferably prescription, pelleted diet (I prefer Harrison's High Potency). In addition, they should be offered dark leafy greens, cooked sweet potatoes, yams, squash, pumpkin; entire (tops and bottoms) fresh carrots and so forth. No seeds (and that means a mix, or millet, or sprays, etc. etc.) and only healthy, low-fat high fiber people food. A dietary change should be closely monitored and supervised by your avian vet.
Birds should get 12-14 hours dark, quiet, uninterrupted sleep at night. Any less and they can suffer from sleep deprivation and associated illnesses. They should be covered or their cage placed in a dark room that is not used after they go to bed. They should have access to bathing by daily shower, misting, bath bowl, etc.
The cage material should be cleaned everyday, and twice a day if the bird is really messy. Paper towels, newspaper, bath towels are ok. Never use corn cob, sawdust, wood chips, or walnut shell. Consider getting a large cage that is longer than tall--as birds move in a horizontal rather than vertical orientation; and have several feeding stations.
Never give grit, gravel sandpaper or cement perches. A bird will eat those to excess when it is not feeling well or if there is a nutritional deficiency. They do not need it at all (an old myth from the poultry days, even poultry do not need it). It can cause an impaction and lead to serious or fatal consequences.