I am so sorry about your dad. I would hesitate to insist on adding to your burden at this time unless you're the type that needs to be doing things to help deal with stress/worry.
Don't completely rule out an occasional meal from a restaurant during this time. There are always healthy options to order out at most restaurants, so I'd look at a few close to the location and check menus online to see and then write out a few sample orders you can run by her as a fill-in if no one feels like cooking at any point. Having the order, phone number on a few cards, or easily emailed list could be a great help too. She can then just say she doesn't feel like dealing with food prep/ordering and just say "pick a card" or similar to someone else to handle. Definitely don't be shy about asking friends/relatives to help out with food if they offer.
When you say refrigeration is limited/shared, what does this mean? Is this for your mom at her home, or for both parents, while she's visiting him in hospice?
A few easy suggestions:
No cook/refrigeration options:
Seasoned tuna or chicken pouches with crackers.
Canned healthy soups
Organic/no sugar added applesauce or fruit cups
Some brands of instant oatmeal AND protein bars (check labels as some of them have really high sugar/sodium)
Beef jerky, raisins, mixed nuts.
Some assembly/cooking/fridge:
Soups, heated at home and added to thermos.
Beans with rice, with whatever veggies/spices appeal to everyone. This is filling, delicious and healthy.
Whole chickens are easy to cook, and frozen bagged veggies that can be microwaved/steamed in bag are a quick way to get super healthy, easy meat and veg meal. I also do chicken drumsticks either in the oven or slow cooker with some spices and then throw them in a container.
If any of this meal stuff is happening away from home, double check that salt/pepper is available along with basic plates/bowls/utensils. Sucks to be in a workroom/kitchen area that has the basic sink/microwave counter area and nothing whatsoever to work with.
I do a chicken and dumplings mostly because it's comfort food and I make it sort of from scratch, but with a super cheat: I use homemade chicken stock, lots of peas and carrots and white chicken breast (either canned or frozen pre-cooked chunks for quick prep if I don't have freshly cooked chicken on hand) and then I make the dumplings by using the can o' biscuits and flatten them out, cut them with a pizza cutter into small strips, dredge them through a bit of flour and then drop them into the simmer/boil broth, and then once they puff/float, turn down the heat to low simmer and add in a bit of flour stir as needed til the broth turns to gravy. Salt/pepper as needed.
