Your son would put his tuition information on his own tax return. If he doesn't use the full credit himself, then it's possible for him to transfer the credit to you. You would then put the transferred amount on your return.
This FAQ tells you how to claim tuition fees in TurboTax: https://turbotax.community.intuit.ca/community/family-education/help/how-do-i-claim-my-tuition-fees/00/873598
This FAQ tells you how to transfer unused tuition credits: https://turbotax.community.intuit.ca/community/family-education/help/how-do-i-transfer-my-unused-tuition-credits-to-someone-else/00/873652