There must have been something else going on here. My son had Food Protein Induced Enterocolitis Syndrome as an infant. His diet consisted solely of fruit, veg and breastmilk for the first 14 months of his life. Anything else would cause him to violently throw up til he ran out of stomach bile, followed by hours of lethargy. He was in the 99th growth percentile the whole time.
There must have been something else going on here.
A baby could easily thrive on breast milk alone for ten months. I suspect it was lack of breast milk that harmed this child.