Is 31lbs to much for a 15 month old boy?

the doctor told the parents the child is obese. i see them feeding him junk everyday at every meal. for breakfast he will eat cheesy grits, the kind you put in the microwave. for snacks he eats cheetos and chips and they give him sweet tea in his sippy cup. they took him out to a chinese restaraunt adn the child had his own plate with the portions of an adult! me and my husband keep telling them they need to feed him healthier stuff but no one is listening to us. i have a 14 month old son, (the babies are cousins) and seeing the difference is just so surprising. i know all babies are different but i feel bad for the baby and i dont want to see him obese as he grows up bc of the result of the parents. i recently read that 31 lbs is the weight of a 4 year old. yikes! he weighs as much as a 4 year old at 1! the parents and grandparents (the grandparents watch the boy as much as the parents ifnot more and both stuff him with junk) he was eating cereal in his bottle at 2 months also. i just want other opinions. thank you