Andy Farrell has spoken out about his reasons for 'Joining Jack' in an exclusive interview in Dubai, for Wigan TV.
The now England coach says he want to help raise awareness of the disease and "get the message out there."
He's been in Dubai ahead of a special Joining Jack team playing in the country's Rugby 7s Tournament.
He told us:
"Jack is such a cool kid. He's full of energy.
It's hard to imagine what he's going to go through in his life."
And for more - including the full interview with Andy and Shaun Edwards - see www.wiganwarriors.com/tv