Is a 500,000 Baht bank account requirement necessary for an education visa for children in Thailand?

We normally don't do these "asking for a friend" posts because you don't have the answers to questions we might ask about the situation

I think your friend is having a lost in translation with the school There is no financial requirement for a child to get an ED visa

BUT

the 500K baht comes into play when a parent of a foreign child wants to get a visa based on supporting a foreign child enrolled in school here.

That's when you need to show the 500K baht banked money