How old is your little boy? If he is a baby, he may need a bit more kitten training. Usually older cats, even if they are not the mom, will put babies in their place, so your older cats might do that too-- assuming he is smaller and they can sit on him LOL.
I would substitute toys and diversions (throw a rattle ball etc.) if he goes for me or the other cats too much, especially if the other cats are not managing to discipline him on their own.
Another suggestion: I have 5 foster kittens right now and when they "get into a frenzy" and are biting and clawing my bare feet at the same time, or going for my eyelashes, glasses, my watch, buttons on my shirt, or anything very painful, dangerous, or destructive, I give them a little squirt with a water bottle and they get the message. But one important caveat: if you do anything like this, it has to be where they cannot see that it is coming from you.
Many people do not advocate this sort of training, but when you cannot be with the kittens 24 X 7 like their moms are, and they need to learn before going to a new home, it is an effective and non-painful way to teach them. The caveat is, again, they cannot know it is coming from you. Luckily kittens are not all that focussed LOL.
If your kitty's mom were there, she would grab him and wrestle him to the ground and bite his neck to show him when his behavior is out of hand such as what you are suggesting, too much aggression manifested in biting and scratching you. I am assuming you do not play with him with your bare hands or feet, by the way, since that is training him to think of your extremities as toys.
Good luck! You are so nice to come onto the forum for advice in this area! So many people choose to take it into their own hands with horrible consequences!!