This can be gotten midway through the Mini Golf Course on Day 2 (possibly earlier, wasn't tested). This is easiest with 2 controllers.
At the same place you learn the "High-Five to Heal" with
ability, there's an armored boar on a track. Using 2 controllers to control both characters, stand in the path of the boar with one character until they take 10 hits of damage and fall down. Then using the other controller, run to the downed character and press
to pull them back up and heal them a bit. The achievement unlocks instantly.
You may be able to do this a bit earlier with the arrows popping out of ground on the course, but I wasn't sure. The above location was the place I got it.