Cepheus finally drinks milk

Actually in the past, we have tried to spoon feed him as well as putting milk into his straw cup for him to drink, but he refused.  So all along, we have thought that he is rejecting milk.  Then yesterday, Dear suggested why not let him try to drink milk from cup again to see if he will actually drink his milk.  My first impression is that 'nah' he will not.  However, i am so surprised that Cepheus not only do not rejects milk, but actually holds the cup himself to drink it (of course not without making a mess of himself as he tips the cup over trying to play with it).. Dear suggested that the reason he may have rejected cup previously may be because we were still giving him EnfaGrow then.  But since we changed to PediaSure, we have yet to try cup.  So now, we are trying to train Cepheus to drink milk from his cup since he is soon going to school.  However, it takes much effort, as Cepheus will not drink much from cup at one go, but we have to keep coaxing him to drink and play at the same time.  So we are trying 80ml per time, and in a day he can actually take 2-3 times of milk in that way.  I am feeling elated, as i am worried that he is rejecting milk.  Seems like i am wrong and that i believe he will be better at drinking once he go to school, as they will be training him to drink with a cup by self holding it.  And i do not have to worry about sleep feeding him at night time, as it may impair a child's healthy teeth by having milk at night.  I can give him water after drinking milk now since he is wide awake before putting him to bed.