Hi. 

I can understand this must be a freighting time for you this is the worst part of life. Future uncertainty. I know first hand what that's like all I can say is never give up however hard things get. I know it's easier said than done. But you will find a way. Remember only try to change the things you can. Everything else will take care of its self. It may be hard to talk to your dad but if you can try to spend quality time with him and tell him your worries and fears. I'm sure he will understand your fears he may be ill but he is still your dad so If you can speak to him. If you can't speak to him Has he a cancer nurse as they can help you or at least point you in the direction of someone who can give you help. Lastly don't be too proud or think you are to young for help seek and please except all help that you can get.

good luck and  Very best wishes stay strong not only for your dad but more importantly for yourself you can amaze yourself. 

Take care.

S