Matt Hurt’s review published on Letterboxd :
I was really impressed with Craig Roberts' performance in The Fundamentals of Caring. The character is written in such a way that, if the wrong actor performed it, the movie could have struggled to make him likeable. But Roberts takes complete ownership of the role and makes him sympathetic despite his quick-witted and emotionally stand-offish attitude. Paul Rudd plays off of Roberts really well as a caregiver with trauma in his past.
The movie is a nice chracter piece exploring the two central characters' reliance on each other and their growing friendship. They improve upon each other and get each other out of their comfort zones in different ways.
I kept waiting for the movie to take a turn toward a more dramatic path. I'm thankful it didn't because the movie develops the bond between the characters well enough without needing any overtly/expected dramatic turns to hammer it home.