Drywall over it & then decide on a mantle or not.

yes agreed easy fix

Would be nice to see some pictures without the clutter.

And I agree with Sophie ... The fireplace has a timeless design that you should embrace rather than cover up. It has ton of character and proper furniture arrangement and choice will definetly keep it from looking dated.

It won't matter what you do to the fireplace if you don't clean off the tops of the cabinets. I see a very large pot or cooker of some sort. That is far more distracting and far easier to fix.

Ok guys, here's the thing. if she drywalls over it, it will still be there. that is better than paint! pointing out all the faults of her home, (in your eyes) is overwhelming to me I can only imagine how you made her feel. She probably won't come back.

If it were me, I would paint or dry wall over and put a mantle. If you decide to keep as is, perhaps update the insert and add a mantle -- I find the floor to ceiling brick and grid lines with brick placement to be dominating. Breaking it up with a mantle will allow you to break it up the visual dominance.

I have to agree: the question was to help with the brick, not to comment on what she has in the space. Jeesh.