s long as he eats at minimum 8-12 times in 24 hrs, the rest is normal. There is a huge range of normal behavior for newborns & nursing.
II think what you are getting is the newborn boobie drunk pass out. Try removing clothing, keeping him awake to finish, etc...but it may not work, never did with mine.
Read
here & it will help you understand WHY it is happening, but it won't change anything,. It is from a hormone called CCK that aids in digestion, but it also makes some tiny ones very very sleepy.