[1] Brennan's physical recovery was hampered by mental health issues, caused by damage sustained to his head during the bomb attack.
[2] In 2011 his anger management issues led to the collapse of his marriage and his discharge from the Army after being sent home for misbehaviour from a Combined Services skiing camp.
[1] Although Brennan failed to make the team for Beijing, he continued entering sporting programs and in March 2008 he began to learn adaptive skiing.
[5] At the 2013 IPC Alpine Skiing World Championships in La Molina, Spain, he took 9th place in the super combined, but broke his sternum the next day while preparing to compete in the giant slalom.
[3][5] However, after returning to competitive skiing in the southern hemisphere he broke his wrist, which limited his ability to practice and compete prior to the 2014 Winter Paralympics.