Although this is more of a sleep issue than a bfing issue - I may be able to help. I would try feeding him before or after you normally do, you may be hitting him in too deep of sleep cycle. If you have a monitor, listen to him on it and listen for him to stir in his sleep, this will give you a clue as to when he is going through a lighter phase of sleep.
I had to stop the df around 3months old because my ds would wake more often during the night. He was a very deep sleeper, and if that cycle got disrupted he wouldn't get back deep.
FWIW, even when they do "sleep through" they always have waking issues - teething, developmental, growth spurts, gas, etc. They will go through times when they are better sleepers and times they wake many times a night. :wink: