Suggest changing his diaper when he falls asleep
after feeding 7-8 minutes. That will wake him
up enough to feed again hopefully for 7-8 minutes more so he is feeding every 2-3 hours instead of every hour. To supplement the breast milk with infant formula, suggest mixing them. Try mixing ¾ breast milk and ¼ infant formulas at first. If he does accept it, then after a week or so, try doing a bottle mix of ½ breast milk, and ½ formulas.