You can always order delivery for them, wherever they are. Ask them where and what they like to eat and order from there. Order double so they can reheat for a couple of days. Then, repeat.
Tell MIL that this saves her time and she can still provide the fruits/vegetables and other snacks.

I have had great luck sending premade, frozen meals to new moms etc... using igourmet, honeybaked ham, and omaha steaks.

Look into Schwann's and see if they deliver in their area.

Do they live in the DC area? You can try www.mommemeals.com

If your MIL is ok with some prep, Blue Apron is a great food delivery service. All the ingredients are pre-measured but there is some chopping and other prep needed (usually less than 25 minutes). I saw Gilt running a special today.

FIL had surgery recently. It's come to my attention that he is not eating well (well, he didn't eat well before, but I feel like it's worse now and matters more now). I would like to have some meals sent. 1) Any recommendations of meal delivery service? 2) How not to turn this into an issue with my MIL (she cooks but he doesn't like what she cooks). 3) Will they eat it?

What do you all think?