I’d like to make some rudimentary professional recommendations based on this short clip to view:

1) use Benjamin Moore vegetable based paint to paint the rusty cage bars. Birds will “mouth” their cages and deteriorating metal/ rust is highly toxic. Heavy metal poisoning is quickly lethal.
2) clean the bottom of the cage everyday to avoid that amount of waste build-up. Ammonia from waste is caustic and birds have particularly sensitive mucous membranes and are highly susceptible to lung infections including pneumonia. Pneumonia can quickly be lethal in birds.
3) empty, soak/sterilize w 1 bleach : 50 water the food dish. It’s most helpful to let the dish come to completely dry before reusing to best kill bacteria. Chlorine from bleach also takes 24hrs to dissipate so rotating food dishes while 1 sits out of cage bleached/ then sits for every-other-day is the smartest husbandry choice.
4) I advise the same practice with your water dish. A water bottle is more sanitary. However, even a water bottle After 2 days has high bacteria load growing in the water from backwash & a bottle will become “infected” water or too high a bacteria load. So you need to at least clean/ soak/ &/or rotate your water bottle every-other-day to ideally, daily.
5) Very young and very old birds are more susceptible to illness from environmental hazards. Have that bird vetted. The body feathers don’t look like a young bird. The missing neck feathers, or last feathers to grow in on a young bird, could indicate emotional stress or physical illness when seen in mature birds. Birds go downhill fast and are harder to treat w such a limitation on western medicine answers for them. Act fast and make all these changes today to support health if this bird.

Addendum: I re-watched and notice your now obviously very young bird is on concrete w water stains indicating this cage is likely outdoors. If this bird is on continental USA, he/she needs indoor climate control.