principles for british values and for freedom. reporter: they came here to fulfill costa s wish to bring home and capture isis flag for his former colleagues in the marines. my brother never got to complete that mission. so i m going to help him do it. reporter: cnn first met jordan in syria last october, where he was making light of the challenges. second day in i got hit by a mortar in my on a flight. reporter: nine months later, standing by his friend s grave in central england, he s overwhelmed by emotion. when his own nation wasn t willing to step up and do something, he did. so i think as an honor to have known him. reporter: jordan and costa both in this photo were fighting in northern syria with the militia known as the ypg, the local kurds fighting to drive isis from their towns and villages. they re most famous for their battle of kobani where international air power helped push isis out of the key town by