Some questions

Would it have been acceptable to go ahead with the surgery without informing Dr X?

No. When Dr. X is in possession of his senses, he has to be consulted and his decision honoured.

Would it have been okay if the tumour was believed to have affected the patient’s ability to understand the situation?

Yes. When he is not in full possession of his senses, his next of kin must decide in his best interests.

Would it have been okay if the chances of recovery following surgery were low?

No. If the chances of recovery were low, the decision on whether or not to operate must be taken even more carefully and the patient’s choice ascertained.