As I noted in my original response, please get in touch with TMEA on a unique question like this. The reason eligibility may apply with that 15-day rule is on the linked side-by-side document at the bottom of TMEA's eligibility policy. (https://www.tmea.org/all-state/eligibility/) Generally, I read that as all items are applicable in that case. The 15-day waiting rule is not limited to athletics per UIL.

What could help is if the student was enrolled before the winter break. Fifteen days is not school days but calendar days, which we've all passed probably between the beginning of breaks and the Area hearing date.

Please email TMEA if you haven't already in a case like this. They will have experienced this question many times before and be able to give the proper response. The Yellow Board can be helpful, but I would never trust it on an eligibility question! There are so many factors at play. I will say TMEA tends to rule in the best way it can for the student on issues, so hopefully the student is eligible.