Baby never wants to eat?

My son is almost 11 months old, 18 pounds. and only eats about 8 oz a day, 1 bottle! I offer him other foods and he’s not interested at all. He’s healthy but just doesn’t want to eat ever. Is force feeding wrong? I don’t want him to not be gaining weight. He’s always been like this since he was a newborn. Just is barely ever interested. He’s not super skinny, he has rolls but my sisters baby is a month old and eats far more than my almost year old. I don’t know what to do? His doctor never says anything about it or is ever worried.