When I answer the questions in Turbo Tax, he gets removed as a dependent if I say he made more than $4000. I then have to add him separately as a student later on under education and it's not changing his non-dependent status. I pay for most of his expenses including tuition, room and board, computer expenses, etc.
If he is 23 or less (as of 12/31/16) then he can be a dependent and you are in the wrong part of the interview. You need to say he lives with you all year (if he is away at school he counts as living with you). Try deleting him as a dependent and then add him back with the correct "lives with" info. Also double check his age and birthdate.