if my son got an in school suspension are they allowed to purposely give him no work to do all day long even when he asks for work

That's a matter to take up with the school and see what the school's policy is.  It could be part of the consequences that the student is not allowed to do work, and then has to make up the work, amking the suspension worse because of the boredom factor.  You should discuss this policy with the administration of the school.