Stumbled upon this thread and remembered how I picked up my cat from the street. Can say that it's extremely important to bring the kitten to a vet as fast as possible. You can't really help him by yourself in that state. Mine looked battered, thin and obviously infested with fleas and helminths. We struggled with fleas for a month, eventually, some pieces of advice from
this article helped. As for the other troubles... vet gave us a ton of prescription meds.
Hope you managed to help that poor kitty.