A weight of 9.8 kg for 13 month old is excellent, even though I would like to know the rate of growth and if the baby has recently lost any weight. so considering that this weight is fine , the baby is getting enough calories and only food if the baby doesn't eat fruits and vegetables should be from the milk.. it is advised to give only 500 milk ml of milk and milk products per day to your child above age 1 year . so try decreasing the milk and the baby will start eating more. Encourage the baby to self feed rather than force feeding.

If your son is on bottle feeds and getting a lot of milk there usually is a dislike towards solids.Since his weight is normal there is not much to worry about but I would suggest to slowly come down on the milk feeds and increase the solid feeds.