He looks about a week old. Are the droppings normal? Should be brown and firm with a white dot (depending on the food he got fed).
The feet looks normal to me. I'm sure if he was internally injured, then he would have died already. Put two fingers on either side of his beak (so that his beak is in the middle). If he nuzzles your fingers, then he must be hungry and needs to be fed. Do you have a handraising formula for baby parrots? Kaytee Exact.
Get some parrot food and also a jar of human baby applesauce. If the crop is not empty (doesn't look empty) only feed him warmed up diluted applesauce. This will help to get the crop working again. Are you familiar with feeding small babies?
Will it be possible to open his beak and check inside for unusual yellow or whitish growths? You will need a flashlight to check deep inside the back of the throat.
Do you have a small medicine dropper? If so, you can hydrate him by holding the dropper next to his beak (so that the droplet touches the beak). Just keep away from nostrils. Just give ordinary water, no sugar or salt added.
You will need to get food into him. Did you manage to get the handrearing formula? Mix to the consistency of tomato ketchup. Formula needs to be warm. To this you can add some applesauce. You will need something where he can stick his beak inside to eat. A cut-off syringe works will. Also continue to keep him warm as he needs heat for the food to digest. No need for extra water. Try to feed him 10 ml for a start.
The droppings don't look too bad. One doesn't know what he got fed by the parents before you found him.
Get a bag of frozen peas from your supermarket. Defrost in warm water. Remove the skins and blend them very well till a soft consistency. Add some applesauce and feed this to him. The droppings will change when this gets digested. Will be green and mushy, but that is ok.
Is there no way you can check inside his beak? This is very important. Yeast will show as whitish plaques deep inside the throat, canker will show as cheesy yellow growths. Is there any way you can get hold of Nystatin for treating yeast? Also metronidazole for canker, just for in case you need this. In a petshop, that sells fish equipment, one can buy Fishzole (same as metronidazole).
He is definitely sick. By now he should have been so hungry and eager to eat.
I'm really surprised he is still alive. I think if he was bleeding on the inside, he would have died already. What happens when he has these seizures? Does he fall to the front and convulse while flapping the wings?
Will you be able to get very small baby peas to handfeed to him? Otherwise when you get the formula, mix with a little bit of water to form a soft clay. Then make small balls and feed to him. Just make sure you are putting the balls over his tongue into the back of the throat. He will need to drink water when you are feeding the balls as this makes them very thirsty. This way of handfeeding might be easier than using a syringe.
Just be firm. Put him on your lap against your body. Have a firm grip on his beak when you open it. He won't last much longer if he is not getting fed.
He won't survive for much longer if you can't get food into him. Even an adult can't survive for longer than 3 days without food. Try to wedge a fingernail inbetween the upper and lower beak and then grab the lower beak and push it down so that the beak opens.
Problem is, if he has canker growths inside the throat and you feed him solid food this can cause bleeding. Only alternative will be to use a 1 ml syringe and feed him formula. If you can get the syringe past his breathing hole he won't aspirate. Little bits at a time.