Ok ... so I think you are asking if you file an injured spouse form will you get the EIC portion of the refund based on your SS income. Answer is NO ... the EIC is based on his earned income from wages and none of it actually belongs to you. If you filed separately none of that credit would show on your individual form so there is no benefit to filing the form 8879. The only benefit is the debt is being paid down by the government and not him.