Is Biopsy Essential For Diagnosis Of Hyperechoic Endometrium?

My mom (75) was diagnosed with hyperechoic endometrium. Thickness 12 mm. She is not bleeding, she has no abdominal pain or other symptoms. It was diagnosed on her yearly check up visit. She said she was diagnosed with it also 2 years ago but that time her MD do not recommend biopsy. This time doctor suggested biopsy and she is really scared as she was not explained almost anything including the whole risks of having thickened endometrium. Since she is not having any symptoms, would you suggest biopsy, or just leaving it the way it is considering her age and risk of this procedure? Mom has elevated blood pressure well controlled with medications, and atrial fib. She does not take any hormonal therapy. she is on daily thyroxine. Thank you. aggie.