Holder rode in the same sport that has seriously injured his best mate. Holder has had serious injuries himself - and yet still rode in the GP to honour his mate. Racing in the same sport as your mate was seriously injured must be far more nerve-wracking for a rider..
Dak won't/can't ride because his father is injured - but also won't/can't fly home - unless you believe that Ford won't let him ride... I believe Dak's father is an ex-speedway rider. I'm not sure that he'd be happy that Dak is staying at home - yet not riding. Maybe Dak's mum assumes that Dak is riding and has suggested that, rather than let his team down, he stays in England as it seems that the injuries are not life-threatening. (All supposition on my part).
The question that needs answering is whether it is Dak or Matt Ford who is stopping Dak from riding.