1098-T and AOTC

I am helping my niece and sister-in-law with taxes.  My niece received her 1098-T from college and has more scholarships, etc than qualified expenses, so she will need to claim the excess as income on her return.  However, she did pay tuition out of pocket in the summer of 2018 because not as much aid is available during the summer.  The questions are:  Would the out of pocket tuition cost be eligible for the AOTC and filed on her mom's return?  Would the 1098-T information need to go on both of their returns?  It will be entered on my nieces to claim excess scholarships and grants as income.  When I enter it on her moms return, it indicates no eligibility for any education credits.  How do we make this work correctly so that she can claim a credit for those tuition costs that my niece paid?