How is the 1098-T "amount billed" supposed to be claimed for tax credit?

My friend's 2017 1098-T has the amount billed for his Fall '17 and Spring '18 (He registered in 2017 for spring courses) courses but for his scholarships and grants it only shows the amount he was rewarded in 2017 and not in 2018. In reality, his courses are paid for he just doesn't have all scholarships and grants present on 1098-T due to it being awarded in 2018. Can he still claim the amount billed or does he have to claim what was actually paid in 2017 ? If he does claim the amount billed what will happen? Can he just claim the amount billed in box 2 and not file the 1098-T on his 2018 tax return?