So I found some oil puddles on the ground today and found that my rear diff is leaking. I had my ABS/Parking Brake come on yesterday and today I find the leak. The breather tube seems like it got snapped off on the end and I tried moving it and it can go all the way into the diff or pull out to it's current position. What has happened and how can I fix it?

 

That is not a vent tube. The vent tube is screwed onto the top of the left axle tube, it bolts into the rear brake T. It looks like you backed up into something which punctured your cover. Hopefully, everything is okay inside. Get a new cover, or remove it and weld it up.