Complex sentence: Butler was part of a "YouTube Boyband", a group involving Jim Chapman, Alfie Deyes, Joe Sugg, and Caspar Lee that raised money and awareness for Comic Relief.
Split into simpler sentences: Butler was part of a "YouTube Boyband", a group creation created to raise awareness. Also involving Jim Chapman, Alfie Deyes, Joe Sugg, and Caspar Lee; they raised money and awareness for Comic Relief.