Hello katyw.  Welcome to this forum.  How awful about your dad.  It is frightening when as well as facing losing your dad you are also worried about what it may mean for you all.   After the loss of  your grandad your family must feel that your world is being torn apart.  I am sure you will do everything possible to help your mum and give love and care to your dad but this is a hard burden for people of your age to handle.  I am attaching a link to an organisation called riprap which contains information for and by young people who have a parent with cancer.  I hope you might find it useful and you are able to comtalk to others in the same boat as yourself.

www.riprap.org.uk/.../

Make sure that the people who are important in your life (friends, school teacher for instance) know what you are going through so they can understand why you are sometimes finding it difficult to cope. I know you are worried about what the future holds but really for the time being I should just go with what is happening now and keep close to your family.  The practical things will get sorted but there is a limit to what you can do at this time.  And I hope you will return here if we can help you at all.  Best wishes.  Annie