I have to assume that this kitten is still feeding from Mum because it would be very cruel to remove him before this time. Although at six weeks a kitten is taking very little from his mum, by way of food, he'll still be getting vital grooming, socialisation & care from her up to around 8 weeks. You will have a much happier confident kitten to go to a new home & it is much better able to adapt to life without mum & littermates after 8 weeks than 6. When homing my kittens ( at 12-13weeks) I send a care pack containing; a small supply of food & litter that they are used to, a diet sheet, instructions on changing these, worming dates & my phone number for new owners to ring with any problems plus back up if rehoming is required for any reason. If homing to a home with resident cats I always recommend following GCCF guidelines to home after completeing innoculations at 12 to13 weeks.
If you want your kitten to reach it's full potental I recommed using a kitten food ( ad lib, soft & biscuits) plus treats of cooked white fish/chicken for the first 12 months. Lots of luck with your kitten.