Weight and nasty comments

[soulB]

Hi,
I am a first time poster and not sure where to ask help or who to refer.My 9 year old boy is taller than average kid and is on borderline obese category (not slim but not heavy weight either in between to be presice) Grade 2 he was commented on his height and not in grade 3 ,kids in bus aswell as in School say him"fat guy"
It breaks my heart.I try my best to gather his courage and go to school
Today I got call from school that a younger class kid has called him fat in front of whole class and these are teachers words"he stood blank for good 2-3mins"
My tears are nonstop rolling and I don't know what I can do to protect my child.Help me what should I do?