Herb (2007)

both movies are about people who have disabilities, both have the issue of overcoming these disabilities and fall in love with a normal person

They are both about mental disabled adults coping with their family and falling in love with individuals who are not disabled.

Both have mentally handicapped female leads. Both have some comedy thrown in. In My Sister of Eternal flower, the protagonist's siblings each have their own side stories.

Both are coming of age dramas about women with mental disabilities. Both have a great Mother/Daughter relationships (Daisuki has two!).
There are other similarities such as good character growth for all concerned.
Daisuki is more involved showing the protagonist, Yuzu's, struggles to raise her 'normal' daughter without too much sugar coating.

A bullying movie that shocks! At the same time it teaches us a true lesson and irritates us in the form of the mundane injustices of our world!