If she is adding new cabinetry, explore the option of swapping out the old doors and drawer fronts for new ones matching the new cabinetry. A lot more to discuss and decide before properly advising - diy? Contractor? Pre-finished? Raw wood and finishing herself? Etc....

Here's one we redesigned and rebuilt where we swapped out all the doors and drawer fronts, then refinished everything (along with new tops, tiles, lighting, etc....):

Same kitchen before:

Yes, it will look a little odd to the "must be just so" crowd, but I prefer to own my kitchen instead of it owning me. If that is what works for her budget and design sense, who are we to say no? If done well, it will be hard to notice once the kitchen is being used. If the hardware and the paint match and the layout makes sense, it will be fine if the house is not at the top end of the market.

Years ago, I bought a foreclosed home with a large kitchen. Most of the cabinets were white but the latter addition across the walkway were slightly different style and still natural wood. We swapped the fridge and pantry cabinet, added oak flooring and painted all the cabinets to match. After several days of working in this kitchen, we noticed that the cabinets were actually a mix of two sets. We first noticed that the drawer styles didn't match across the room and finally saw the doors did not match either. We painted all the cabinets in the same paint and no one ever commented on the three different styles. Tons of visitors all said how much they liked the kitchen which was much larger than expected for the age and price of the house.

A cabinetmaker can make anything you need. I had all my cabinetry done by a local guy and my doors were a custom designer.

There are plenty of doors available with arched styles when I looked - even places that sell only doors seem to have this style door available for those who want or need it.

Check a local cabinet maker and your friend can extend the run of cabinets far less expensively than changing all the other doors.

Also, the eye compares items which are next to each other. If there are three cabinets in a row, it is easy to see when one doesn't match. However, have two cabinets, a bookcase and then another cabinet and the differences are much less obvious.

Thank you for the suggestion. She had the kitchen done about 8 years ago and is now removing a wall. So the cabinets will be added to the back wall.