L.U.
Every child is different. If he has no health risk from milk then that it good. Weaning will take time and consistency as such when potty training comes into play. If he is able to hold the sippy cup, then just use that consistently. If he refuses, place it in view and tell him your going to put his milk there. He may tantrum, and you will again offer to him nicely again. If he refuse, you will repeat this. He will identify this as his drink, he will soon associate that drink with your comforting offer. Praising his good behaviors. In time, you have modeled speech; better coping; praising to good behaviors. ..... I know it takes time, in the long run, you would be so proud of yourselves. As such, for being so concerned as you are now.