Only the person who claims the student as a dependent can claim the tuition credit, regardless of who paid the tuition.
But that is not true for a 529 plan distribution. If the mom got a 1099-Q for a 529 distribution, she can count some of the student's expenses (including all the room and board) to make the distribution not taxable or less taxable. If the distribution is fully covered by expenses, she does not need to report the 1099-Q.
Q. Plugging in the 1098-T said it didn't help my taxes at all. Is there anything I'm mandated to do?
A. The usual reason for not qualifying for the tuition credit is that your income is too high (>$90K Single or HOH). The 2nd reason is scholarship was too much (but there's a workaround for that). If that's not it, you entered something wrong.
You will need to do some coordinating with the mom and maybe the student in allocating the expenses for the best tax benefit. If you're not eligible for the tuition credit, consider letting the mom claim the student as a dependent this year. The credit is worth as much as $2500 to her (plus the [up to] $500 dependent credit) vs the $500 dependent credit you give up.
