See if you can borrow a have-a-heart trap from the humane society or a rescue group. He needs to be seen by a vet, and at that age, if he's healthy, he has a great chance to become an "ex-feral" and get socialization. He may, though, be sick, or even be a "wobble kitty" - a mom with feline distemper can give birth to kittens with cerebellar hypoplasia, which can cause difficulty with motor skills. He really needs to be seen by and diagnosed by a vet. If someone can bring a towel and catch him by throwing the towel over him then scooping him up, towel and all, you can get him to a vet. 6 weeks isn't the optimal age to be away from mama, but it isn't a death sentance either, if he's given care.