It would probably benefit from having a bird friend about the same size.
If you have the patience to feed it ... I would be offering rotten bananas, apple sauce etc. to the tip of its beak, careful not to cover the airholes.
I think the best working assumption is that, The Animal wants to Live. So, treat it accordingly, unless/until it dies.
I had a Silkie with a bum leg that learned to get around on one leg, a kind of hopping/ flying that she became quite proficient at.
I named her "Ralphie" after the Ralph Macchio character in Karate Kid. At the end of the movie, he is getting around on 1/2 a leg.
I had her for about 2 years and then re-homed her. She loved being with the other birds. She would hop to a roost 4 feet off the ground, to be near the birds 10 feet off the ground.