I have known hims work since I was a child.

Know sort of works, but makes it seem like you knew him personally

He wrote the musics for the films of Sergio Leone.

I have just seenaw "Once upon a time in the west".

sounds more natural

Now I would like to see theLeone's other films of Leone.

Both of these are equally correct, but a native english speaker would always use Leone's.

Ennio Morricone was an iItalian song writer, h. He died two weeks ago.

You can also use a semicolon.

I have known of him since I was a child.

One can "know" famous people in the sense of recognizing their names or knowing of their work, but it's a somewhat informal usage.

At home, there was a best ofcompilation album of hims and I have always loved his songs.

He wrote the musics for the films of Sergio Leone.

I have just seen "Once uUpon a tTime in the wWest".

The work uses title case, so we should use it here as well.

The music and the movie really matchwork well together.

Ennio Morricone was an iItalian song writer, he who died two weeks ago.

I have known him since I was a child.

At home there was a "best of of him" album of his music and I have always loved his songs.

He wrote the musicsountracks for the films of Sergio Leone.

La musique ne peut pas devenir musiques

I have just seen "Once uUpon a tTime in the wWest"."