4. 5 months old dont take feed while

Hi, my son is now 4.5 months old and he still doesn't take feed in awake condition. We have to make him drowsy then only he takes feed. I heard that in general we have to feed on demand to babies around this age but our baby won't ask for food for hours and if he feels hungry, he will prefer sleep over feeding. This made him caused weight loose when he was 3.5 months old. We then put again 2 to 3 hours frequency feeding for him even though at night and he gained proper weight as per general weight chart. But my worry is why we still need to make him drowsy to feed as he still doesn't take feed in awake condition even though he wants milk? He takes time to become drowsy as well and cry that time. I googled about it and I read about feeding aversion and sleep association feeding are the topics pertaining to this. If we  go like this, will my child prefer to feed in sleep or drowsy conditions or will it change over time??