When a story begins, everything is normal, it may not be normal for you and me but it is the norm for the character.

For instance a young girl lives in the middle of nowhere Kansas, she doesn’t like it there and wishes she could leave.

Then something happens; a tornado picks up her house and drops her and her dog Toto in the magical land of OZ

As a direct result of this event the character must do something, The character will have a goal and a usually must achieve something to accomplish that goal
for instance, the young girl must get back home (Goal) and in order to achieve that goal she must get to the Wizard
who lives in the Emerald city.

When the story concludes the young girl who thought her little town was horrible, now understands there is no place like home.
There is character growth.

What you have described in your logline is ‘life as normal’
What event happens which will cause your character to have a goal?
Add that and your logline will improve greatly

Hope that helped.

Saving her brother is a better goal, I would just drop the “Expose the doctor” angle from the logline.
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“When she receives the ability of mind control after a delusional doctor switches her pills, she must now use her new ability to save her bother who is being held also.”