Complex sentence: This was Raj Kapoor's last leading film role and was also the first and only time he appeared onscreen with his brother Shashi, not counting Awara, wherein Shashi Kapoor appeared as a child actor.
Split into simpler sentences: This was Raj Kapoor's last leading film role and was also the first and only time he appeared onscreen with his brother Shashi. That is if we discount Awara wherein Shashi Kapoor appeared as a child actor.