Visited my ILs last week. My MIL is pleasant but can be overbearing, very involved in her daughter's life, and very black and white.
My DH has a younger sister, age 24, who is living back home for a bit to save money after her Masters finished. She's lived independently in another city 150 miles away for 4+ years.
MIL told us that SIL had been poorly with a virus, potentially an ear infection. Booked a doctors appointment locally, MIL told us what she said to the doctor and their conversation (including calling the doctor a quack for not examining her), and it sounds like SIL was sat in silence. SIL was out at the time so didn't get her version of events.
Coming away I was gobsmacked that a parent would accompany an adult child to the GP. She's 24! There's no reason why she can't advocate for herself.
I do understand parents being worried, SIL does have asthma and allergies that have affected her over the years.