Then help him try to get it all put together in time for his class, which isn’t possible anyway so he might as well throw himself on the mercy of his teacher and take the late grade!
At this point I’d just go to the teacher, admit I messed up, and see about how to make it right. The grade he’d get wouldn’t be any worse than the one that’ll result from trying to throw one together at the last minute.
Now they’ll go to class and find out the teacher’s out sick so the volcanoes aren’t due until the next day!