hi - i think that at 27 months he is well old enough to come off a bottle!! my youngest is 17 months old and he has been having a beaker since he has been about 11 months old, all my children still have a bedtime drink however, they all have cup/beaker of warm milk i guess its a comfort thing, dont worry about him going thro the night, they all decide when they are ready my 4 yo was dry just after potty training during the day at 2 1/2 but my older boys were ages before they went thro the night, and my friends little girl has only been dry at night since she turned 5!!! so every child will be dirfferent, dont worry!!! xxx