No - Your son does not have to file either a Missouri or an IL return.
- He does not have to file a MO return because he is not required to
file a federal return.
- He does not to have to file an IL because he is not required to
file a federal return and his IL income is less than $2,225.
He can file a state return if he wishes to get back any taxes withheld from his paycheck.
IMPORTANT: If your son does
file his own return make sure he indicates on it that HE IS A DEPENDENT OF
SOMEONE ELSE.