14 month old waking up at night for a feeding...?

Hi:) I am a mother of two children. My first one is almost 4 and is a girl and my 14 month old is a boy. My son is a very healthy 14 month old 100 percentile in both height and weight. I don't know if he is going through a growth spurt or something, but at night my mom (he sleeps with my mom...he loves grandma:) says that he wakes up (he never cries just keeps moving around and gets fussy) whenever he has a dirty diaper and wakes up half asleep looking for a bottle. I tell her to try and give him a pacifier but she says that usually he doesn't take it. He only takes it after he has his full bottle of milk and the thing is that he finishes the WHOLE bottle so I know it isn't a comfort thing. He is the kind of kid that if he is done he throws the bottle and goes to sleep. I feel bad for my mom that he wakes up every 4-5 hours for a feeding. My daugther did a similar thing, but I knew she used the bottle for comfort cause she never finished her bottle, but my son sucks them bone dry. Do you think that he is just hungry and maybe hitting a growth spurt? He is really isn't interested in eating during the day which may contribute to his night feeding. He is more interested in playing. He only eats a little during meal times and wants to hurry and go play. Have any parents been through this? Oh and I don't beleive in CIO method...never have sorry. I would appreciate serious answers only. Thank you so much!!:)