I made a recommendation for a "Behavioral Tracker" a couple of months ago, and Med Help replied that they would "add it to their list of to-do's". (I had asked specifically about ADD/ADHD, Asperger's, and Autism behaviors. Perhaps after reading your post, MedHelp will consider including symptoms of ODD on the tracker as well.)
While that may be available sometime in the future, MedHelp currently has a mood tracker that might be helpful to you. In settings there is an option to switch the user from "Myself", to "Someone else" so that you can track their symptoms. Also, in the treatments section, there is an option for "ADD/ADHD meds". I hope this helps! :)
ADHD is not a mood disorder, so we would like to introduce a Behavioral Tracker as halbashes requested. Feel free to use the Mood Tracker to track mood, but since ADHD is not a mood disorder, this tracker does not cover everything that may be important for an ADHD tracker.
Here's a link to the Mood Tracker: http://www.medhelp.org/land/mood-tracker
We'll let you know when a Behavioral Tracker is available.