Local meal delivery services (e.g., Territory, Mighty Meals, etc in the DC area) are usually best because they can be fresher (refrigerated vs. frozen). There is probably at least one service like that near your relative.
Without knowing where your relative lives (general area), I can only suggest nationwide services which come frozen. Some examples are:
Freshly
https://www.freshly.com/
Daily Harvest
https://get.daily-harvest.com/
Mosaic
https://www.mosaicfoods.com/
and Home Bistro
https://homebistro.com/
To send meals to my mother, I have used Silver Cuisine
https://www.silvercuisine.com/ which is marketed towards seniors but is the only way to order BistroMD food as individual meals vs. a recurring plan; the meals and portion sizes are the same for all ages. BistroMD is marketed for weight loss but isn’t really diet food. They provide detailed nutritional information for each meal and highlight some as: heart healthy, low sodium, low sugar, gluten free, dairy free, vegetarian, etc. Each single-serving meal is packaged separately and all you have to do is heat it.
I hope that your relative gets well soon!