Absolutely bf him when he needs it! My son is 3.5, still happily boobing and co-sleeping. I night weaned not long ago because I'm pregnant and don't wanna feed two kids at night, but I believe that children need to feel they can be comforted at all times.

I am going to assume your question is based on the fear that you are creating a bad habit for your son? Look at it like this (if I'm right) your son will know he is safe and secure, and that he can come to you if he needs to, so he will not form bad habits from it, he will form healthy attachment to you, and personal security! And those are fantastic things