How much money do we ask for for personal injury in hospital?

My husband was admitted to hospital in April 2017. He had to have an MRI and was sedated for it. He was wearing a nicotine patch, which they did not remove prior to the test. Towards the end of the test, he was awakened and started telling that he was burning and the nurse grabbed his hand and told him to hold on just a little longer. When they pulled him out, they realized what had happened. They brought him to the room and explained and apologized to both of us. The head of the MRI department then came up and apologized. That was a Friday. He was suppose to have been discharged on Saturday morning, but they now wanted to keep him and treat the burn and send him home Sunday. On Saturday, the gave him way to much Oxycontin ER and he became lethargic, almost comatose and was moved to ICU early Sunday morning. He was given narcan to reverse the affect. On Monday, the hospital CEO came to discuss the test issues we had had, and was apologetic. Since then we have received a letter from risk management and they have stated we can send a letter with a sensible monetary request and they would consider it. No attorney will take the case. We don't know what amount???