Is your collegue certain it is blood? You can test it out by mopping a bit up with kitchen roll. If it clots it's blood, urine doesn't clot, it just dries.
I'm horrified that the vet said that.
I think your friend should find a rabbit-savy vet and take her rabbit for a check-up as soon as possible.
I dont know what vet they use! Dont think its the same as us as ours is very rabbit savvy.
The rabbit knowledge of some vets is shocking. :shock: