Answer:
I read a lot of Percy Jackson stuff, but in my opinion, Grover is bullied because he keeps messing up on every quest he goes on. He also gets made fun of because he lost his Card to be able to search for Pan the lost god. Another thing is he is not full grown and is scared of almost everything and the halfbloods he finds save him all the time, even tho he should be saving them.
Step-by-step explanation:
Hopefully this helps