StarBiker

If that Trek 2014 FX 7.3 I have fit me I would definitely ride it. Solid very light bike that you will be completely upright riding.

I don't know how the modern Trek FX bikes are.

I like veganbikes recommendation.

I know their selection can be limited, and one may not be near by, but check REI. Get a membership for $30, it's a lifetime one time payment. They give you a one year return policy no questions asked. That way if you buy a bike, and it doesn't work for her you can return it for a refund. And if it does you get a 10% dividend after a year to use for something in the store/online.
I am certain as long as you save your receipt (A novel concept for some folks) you can return without a membership, but you won't get that dividend after a year.

I think there are some solid recent used options out there, but you don't know if they will work for her.........