In old days when alcohol was used in surgery, was it's purpose to knocked the person out like anesthesia or just try and dull the pain?

Knockout: Alcohol was given to the patient to make them close to loss of consciousness or deep sleep. Unfortunately that did not relieve the pain.

Anesthetic: Alcohol was expected to knock the person out, like anesthesia.

Either one: Those were brutal times. It didn't work well. I hope you and your friends are grateful to live in an era with anesthesia, aseptic surgery, antibiotics, and safe obstetrical care.

My guess - second: I don't think it is well documented; alcohol has a narrow therapeutic margin, meaning the difference between the dose for the desired effect ( here: inability to feel pain) and the toxic dose, leading to complications, is very small. So i would guess - the latter, to dull sensations.