"My mother was sent home with a Warfarin level of 5"

On an early November morning, my 81 year old mother was seen at St. Peter's Hospital for an extremely heavy nose bleed. She was also bleeding from her eyes. At the hospital her blood was examined and she was found to have a level of blood thinning medicine (Warfarin) that was twice as high as it ought to have been. The bleeding was stemmed, she was sent home and advised to stop the Warfarin and phone the doctor on the following Monday.

A scant 24 hours later the same thing happened again. My mother lost another large amount of blood, had to ring 999, went back to St. Peter's and was this time transferred to the Royal Surrey Hospital in Guildford. With such a high Warfarin level, why was she not admitted to hospital right away? I am worried she could have bled to death that following night. I don't know how to find out who made the decision to send my mother home that morning, but I sure hope they can be told what happened so they don't do something like that again.