First choice, I would glue it, if it looks like its gonna fall off any how, I would "clip it" back to solid nail.
Vet wrap or any other bandage on most dogs feet is a waste of time.For one, they most times chew it off, if they leave a bandage on, it gets wet and nasty, and makes things worse than leaving it open.
There are a number of good fixes, but hard to suggest anything more without looking at the foot.
Most times,I cut off the split nail, give the dog a shot of "Penn", and keep on going.