Favorite easy-to-swallow soups & purees?

[readingredhead]

We just found out that my grandfather has esophageal cancer, and while the prospect of chemo & radiation is bad enough, he's also frustrated that he can't eat most of his favorite foods! His tumor makes swallowing painful, so while he wants his "meat and potatoes," soups are pretty much the only things he can eat without pain. My mom has been making him a big batch of a different soup every week but we're not much of a soup family and she's running out of ideas.

So, I would love suggestions for flavorful soups that either are purees or can be blended so there aren't any large chunks or pieces (smoother is better). No dietary restrictions, but we are especially trying to find heartier/higher-calorie options, because even soup becomes painful to eat after a point and we want to make sure he's getting enough calories in a diet consisting of mostly smaller portions.

Kitchen equipment is not a problem (we have a slow-cooker, immersion blender, food processor, etc.). For my mom's sake, I'd appreciate recipes that don't require too much prep or "minding," but I know if she were writing this post instead of me, she'd tell you she's looking for the best-tasting comfort-food-ish recipes, no matter how much prep they require.

Really, any and all suggestions are more than welcome, and thanks so much in advance for any help you can offer!