hello and welcome to P.T, which state are you from?
thanks a lot for taking care of this bird
1. supplement it with calcium and vitamina and minerals to catch up with growth. i will suggest you to buy this things from human drug store. for calcium, ask for cipcal 500 tablets, cut one tablet into 8 pieces and give one piece to him once a week. for vitamins and minerals, ask for supradyn tablets and scratch the inner part of the tablet as outer part is coated with sugar which is not good, cut about a jowar size part of it and give him once a week
2. his condition is not so good right now, so it may take about 2-3 months for him to get strong enough to fly and escape from other pigeons. you have to take care of him for next few months and dont leave him with other pigeons for now
3. as i could see his poop are just fine and normal in the pics, he wont cause any health issue for you!!
does he eat and drink on his own?? if not feed him matar by force feeding him