JS, just contact a lawyer. I'm sure DL will cover his medical expenses. Delta really makes me sick. It always seems to me that DL flights are the worst as far as pax with carry on luggage. Do you know how tired I am of being one of the few pax whose carry on luggage meets regulations and still can't find overhead space for it!
The woman fled because she didn't want you to sue her, but I think you should track her down even if it's just to have your lawyer send her a scary letter.