Good summary of what happened here:
https://www.insidehighered.com/news/2019/06/10/why-did-university-alabama-return-millions-donor
And NPR interviewed Hugh Culverhouse. You can listen or read the transcript here:
https://www.npr.org/2019/06/10/731385461/university-of-alabama-returns-26-5-million-donation-to-hugh-culverhouse