Cheer Up, Mr. Lee (2019)

they both start of comedic and get heartbreaking in the middle, and both were about bonding and familial love

The story is ALMOST identical. In both a child suddenly appears, the parent-child combo takes a journey somewhere while getting attached to one another. There is also an illness in both. I highly recommend watching ...the one you haven't yet seen?

There are plots revolving around kids, and these two really had great emotions
Both had that unexpected family bonds

When I see big muscle, I immediately remember Grandpa Muscle.
Very cute movie. Sweet little family story
Big but kind.

Both male lead has big muscle, LOL.
They are both sweet, kind hearted,
They are family oriented. A little awkward in social
Strong man big heart

Both male lead has the same mental IQ
Very sweet big heart, soft soul, gentle man
Some comedy, some heart-warming moments

Both has a loving father who use to be firefighter.
Very strong man who safe many lives.
Heartwarming movie/drama..
The young one stole the heart.

both Keys to the Heart and Cheer Up, Mr. Lee are similar with the same kind of family bonding/touching story