It's got 75k miles so values probably flat from here next few years unless he doesn't drive it. Drive it regularly and ur closing in on 100k miles. $$$ for TAs and RBs next few years.
Did he buy the car off the used lot at Hendrick BMW in CLT?
Look at this beauty for only $31k
2011 AW E90 M3/Slick Top/Speed Cloth/No Nav/67K Miles/RB's Done/ + maintenance
https://www.m3post.com/forums/showthread.php?t=1762329