Im looking for a movie where a young man lives in some kind of city with a controlling mother.?

The boy lived with his controlling mother and eventually falls in love
with an older woman. I don't remember a lot about the movie or who
starred in it but i remember at the end it's him and his brother
poisoning their mother or something and killing her. I always thought
the actor for the boy was Dicaprio but im not completely sure. sorry I
cannot be more specific.