Nothing can be done. Only a deadline can force a senior to fight his way out of the siren's clutches. I could get up early and write it tomorrow. Check the syllabus. Regardless of when it's due, you've got to own up and do it sometime, bringing the senior out of the Senioritis spell.
Faculty know how to counter the disease.
Ask Professor Blix who takes attendance each and every day. You can miss three classes, but after that students' grades are significantly docked. I guarantee you every senior will have missed more than three days. They'll miss at least four, but probably average around six absences. The paralysis sets in at the strangest times, despite the best counter attacks.