Linux is based on Richard Stallman’s philosophy which is GPL. The licence CC-BY-NC-ND and CC-BY-ND is incompatible with Linux and GNU philosophy.
As @opendesktop answered both are valid, you can keep your works closed-source. The fault is not of the forkers or the author of La Capitaine. It was of your friend because he could have put CC-ND instead of GPL3, in the repositories El General 3 years ago and Antu 2 years ago, for preventing the author of La Capitaine of forking. It was too late.
As your friend is not in favour of forks, he is in the wrong operational system because fork is a symbol of collaboration, which is inspired by the GPL philosophy. He can work at Microsoft. Matthieu James was a famous icons designer of Faenza and Faience, abandoned Linux world and Canonical and went to work at Microsoft.