Hi, Thank you for posting this question here, I will try to answer it to the best of my ability. When a surgery is performed there is going to be blood loss for sure, they can try to minimize it but it will happen, it is a given. In the case of your father being anemic, he already has a deficiency of blood in him, so to operate in this situation will cause more blood loss and that is not something his body can tolerate. The reason that he has to wait for the colonoscopy is that they want to find the source of bleeding and stop it. As to why they are taking so long and cant run all tests in one go, you need to understand that there are probably other people scheduled to have a colonoscopy done as well, so your father has to wait until his turn, it is just how the system is. Currently your father is being monitored and I am quite sure he is stable, because if he wasnt they wouldnt be taking things slow. Another reason taking things slow is a good idea is so that your father can recover a bit from his head injury. So calm down, I am quite sure the doctors in the hospital are doing all they can to help your father. Just trust them, they know what they are doing. I hope this helped.