Can she find out more about the floor? It almost looks like a mix of woods! Or maybe a mix of prefinished stains. If this is all one variety, stain, and grade, then you are seeing how each plank naturally takes up stain and I don't think that sanding and restaining to a darker color will wipe out all the variation - might make it a little less obvious (but have her send a photo to a refinisher and ask his opinion)

Looks like hickory, will be tricky. Two part bleach might even it out.

Nope so busy it makes her dizzy and I agree. Not her style. I would not have it in my house either. Maybe she can have it sanded and painted.

Why live with something you hate? Offer it on Craigslist and see if someone will buy and take out- then get what whatever she wants.

Welcome to the world of wide plank hickory! Super tough wood. Very busy. Enigmatic floor with HORDES of personality. Sadly the one your friend has just purchased is *probably a lower quality one. There are DOZENS of short boards in the pics. They look to be factory finished which means it can be a total B!tch to refinish. And the planks aren't very thick. It is entirely possible this floor *might not handle a refinish.

Rip it out or cover it up. Wall to wall carpets will work very well for a few years. Then she can save up enough money to remove ($2/sf) and purchase ($9/sf) and replace ($3/sf for install) the entire floor.

The only hope would be to sand, water pop, apply a light stain and coats of finish. For a stain I'd recommend a mix of white pickling stain and a medium brown like Chestnut, probably in the range of 10:1 or 20: 1 to start.

Hickory usually has lots of color variation especially if light colored. It is much harder than other woods so will be a great floor. However, if she hates it, change it. Sanding and refinishing is not inexpensive and will not solve the variation issue. I have very dark engineered hickory and love it.

You can always dye the floor a light brown. For a less potent color, add a reducer to the dye. A chemical stain will work on it , also.

NO PAINTING for crying out loud. Get a floor refinisher and see what is possible IMO the choice is to go darker to even out the color . I really dislike hickory for exactly this reason so I agree if she really hates it remove it sell it and get what she loves.