It's just kids these days. Think they have to be different.

It appears that he broke the pedicle that the antler originates from, probably from fighting but could also be a car, hung in fence, etc. Don't think it will be worse next year, as there is a good chance he will develop an abscess and die before then (fractures to the skull often end that way). But, if he can avoid and abscess, he can survive it (he obviously survived the initial trauma). In that case antler growth will never be the same on that side. Whichever direction the bone re-ossifies is the direction the antler will grow, which is sometimes bad if a tine grows back towards the skin. Another very interesting thing that can happen is if some of the pedicle cells displace to an abnormal location, trauma-induced antler development can occur. This is usually what happens with unicorn deer (3 pedicles). In other cases, antler growth has been generated at different locations around the skull and even from the neck.