S.H.
YES preschool kids are VERY capable of "bullying" and worse.
It does not matter what kind of school they go to, religious or not. It happens in all schools.
Next, you NEED to tell the Teacher, if the teacher does not do anything about it, then you go to the Headmaster.
AND, as a school, they SHOULD have a formal "policy" about bullying. My daughter's school has one as does most schools.
AND, you PROTECT your son.... especially since he is a 'shy' type and not able, at this age, to protect himself.
OR, you have the school SEPARATE the boy and put him into another class.
YOUR son is being bullied- therefore, he is NOT the one who should have to suffer any consequences or repercussions. Understand that.
As a parent, you DO NOT LET IT GO, nor any kind of bullying. Bullying takes many forms. AND you NEED to teach your son, how to SPEAK UP, how to defend/protect himself etc. Otherwise, as he gets older or goes into the next grade levels... he may still be bullied.
Next, WHAT THE HECK are the Teacher's doing about it? I am sure they are NOT that dense... and KNOW that that boy is a "Bully"?
Again, bullying & mean kids do exist in Preschool. Even younger. I have seen them on the playground too. So, teach your son about it.
All the best,
Susan