According to science this is what happens to brain under anesthesia:
Anesthetic drugs cause brain circuits to change their oscillation patterns in particular ways, thereby preventing neurons in different brain regions from communicating with each other. The result is a loss of consciousness—an unnatural state that he compares to a “reversible coma”—that differs from sleep.
Thus, anesthetics seem to cause unconsciousness when they block the brain's ability to integrate information
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743249/
they safely lose consciousness while their bodies are probed and cut open.
https://www.vice.com/en/article/d3489z/this-is-what-happens-to-your-brain-during-anesthesia
With these significant findings. If Solipsist's mind is plugged out under anesthesia for a while, does it disprove solipsism? Or at least proves that he is not the real one? since every other thing will continue to exist during the procedure.