I suppose the issue is what the surgery is for.
If it is for a complaint that would require special handling - e.g. fracture pelvis where to restrain a person could be very dangerous, then special consideration would need to be given.
The CoP may direct that attempts to being him in voluntarily be made, with a specific action plan. Failing that is may be that a decision would have to be made as to whether the risk of him dying during the process of restraint and transport would be graver than the risk of him actually not being transported in for the surgery at all.
For patients of mine who have had to be transported, they have been visited a couple of times to talk to them, then have been told that they will be transported if they do not agree. One of them was tranquilised to enable that to happen. In both cases a private taxi was used to transport the patient.
That being said, there was flexibility in the timing for the move to happen. I am guessing that given that it is potentially major surgery the hospital/surgeon would be unwilling to block slots on surgical lists to have them wasted (when capacity is particularly tight) due to the COVID19 squeeze on resources. This may make the tranquilisation and transportation option one of the only options to avoid a surgical slots being missed with a long wait for another one to be allocated.
The practicalities of enforcing treatment on a patient carry on once the person is through the door of the hospital as a patient cannot generally be operated on straight away without a period of fasting, so there would be time when he/she would be on the ward and may attempt to escape.
There is also the matter of post surgical care - would the person be likely to engage with follow-up care and would any refusal to do so be more deadly that the treatment itself.
I don’t envy you the task of trying to sort this one out!