It varies from judge to judge but in ordinary circumstances some weight would be given to a child's wishes at 13. However, since we are dealing with a child with ADHD who needs routine, the child's wishes (if the child claims to want the change to a 50/50 timeshare) might not have much weight at all.
I think that the bigger argument is that dad does not currently exercise all of the time that he has now...and leaves very early for work and arrives home late.

