Can I use my son's tuition exp I paid of $10K + on my 2018 return? He has not filed 2017 or 2018 return. Can I claim the tuition expense and he can file later?

Your son would have to claim the tuition on his own tax returns first, and then transfer any unused tuition credit to you.

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

This FAQ tells you how to enter tuition transferred from a spouse/partner or a child: https://turbotax.community.intuit.ca/community/family-education/help/how-do-i-enter-tuition-transferred-from-my-spouse-partner-or-my-child/00/873447

If you have TurboTax Live Assist & Review, here is how to talk to a Tax Expert: https://turbotax.community.intuit.ca/community/navigating-turbotax/help/i-m-using-turbotax-live-assist-review-how-do-i-talk-to-a-tax-expert/00/873764