how much weight has to be gained by baby born at 32 weeks with a birth weight of 1750 gms by the time he completed 5 months.and when can we start giving him food

A. Hello mom babies do double up their birth weight by the age of 4 to 6 months and as he was a preterm baby they tend to gain weight in a slow pace .. when the baby is able to balance his head and able to sit well you may start weaning foods from 5 to 6 month onwards initially start with liquids and then gradually move to semi solids and mashed foods