Could be that they'll want a less vivid color palette, but some fun abstract art might be great. The doctor could even invite patients (or schoolkids, in general, or their own kids), to create art, and hang prints of those. A whimsical tree would be good, too. On the ceilings of the exam rooms, something pleasant/comforting is good. Some offices paint ceilings with blue skies and white clouds.
Why not ask the docs if they could get their patients to contribute some of their renderings for display.
I used to have a school teacher for a neighbor and she would often bring stuff the kids had done for mounting/framing.
I framed some of this work and treated it the same as I would for a 'serious' artist. It looked very good in a decent frame.
Picasso once said it took him a lifetime to learn how to paint like a child.
Have a monthly client art contest just pin up work have the clients vote which one is best. Frame those. Prize maybe free office call. Or Go to local elementary and high school ask teacher for some student works to frame and hang in office put name and school on each. Suggest they rotate every year. Donate framed pictures back to schools every year . It would be a double tax write off .. Easy to sell it Once as an expense then as a donation. We keep cost down by using slow moving moulding and matboard/cut offs. I have one clients that we do this with for the last 8 years. Another it has been 10 years.
here are a couple samples.
Try going to local elementary schools asking for student work to display.
We've got an Etsy shop full of things you may find appealing. Also if you see one of our creatives that you like the style of or like any of the art and would like to know what else we've got in a similar style, let me know and I can put you in contact with the right person here. We've got a LOT of demos in the 8x10 and 9x12 sizes from kids parties, teen parties and bachelorette parties that people may also find a good option for some original art at a very attractive price. We start at only $15 for some of the demos!