So earlier today I went and looked at a black audi that was for sale at a local dealership. There were a few cosmetic problems that I was willing to overlook but when I turn the car on....

-Check Engine Light was on
-ABS light on and Brake light flashing
-High idle at first (1,000 rpm) then down to about 800 rpm
-The brake fluid reservoir was completely empty and there were two empty containers of brake fluid in the trunk
-There was also a broken hose in the engine bay (a picture of the hose that was broken is in the picture attached)

Can someone tell me what this hose is and how it being broken would effect the car? and how easy is it to fix the hose?