first off, i have a friend who does work similar to you. for little consents as "can i rub your back", its easy enough. for big decisions, no, i dont think they are able to understand enough to give consent. even normal people have a difficult time understanding doctor lingo, and many doctors refuse to take the time to explain in laymans terms. medical advocates should be a thing, to protect the interests of the patient if a family member cant or wont participate.

second, two sides to the "do no harm".
having worked in oncology for several years, and also from dealing with workmans comp doctors for over a decade, doctors who are arrogant or blind to their own lack of knowledge are far more common than one would think, and they can do harm without intent.

some doctors want to do what they think is best, and adhere to western medicine standards, which arent always the best way to address all symptoms. some doctors also believe that being the trained professional, only they know whats best for the patient, regardless of what the patient tells them. they fail to give their patient any credence.

example: i injured my shoulder at work. after doing some tests, the doctor diagnosed me with neck strain. I went thru years of therapy, but my symptoms never totally resolved. I was left with acute muscle strain from not being able to use my left arm properly.

The doctor negated my belief that my shoulder was involved and refused an MRI because the xray showed no issues. I could not afford to pay for my own MRI.

seven years later, after a severe re-occurence of my symptoms, i went to an outside doctor on my own dime, only to learn that my shoulder had been partially dislocated for seven years. after an arthroscopic surgery, that shoulder is 90% better. however it still left me with exacerbated muscle issues in my back and neck. because it was workmans comp, i had no recourse for damages other than medical expenses.

this is how consent gets thwarted. when the patient does not have the knowledge they put trust in a doctor. if a patient has no economic resources to combat the insurance system by hiring a lawyer, and the doctor refuses to be open to the patients own self knowledge, it becomes a betrayal of trust. its a slippery slope to prove the system meant harm, but at the same time they caused harm thru their own procedures and prejudices.