Thomas eakins painted a surgery he witnessed in person. who is shown in the painting, but was unlikely to be at the actual surgery?

I believe the correct answer is: patient’s mother.

"The Gross Clinic" (also known as "The Clinic of Dr. Gross") is an oil on canvas painting by American artist Thomas Eakins in 1785. The painting is based on a surgery in which Gross treated a young man for osteomyelitis of the femur. The lone woman seen at the painting is considered to be the patient’s mother and had raised many criticisms.