Individuals deal with the disease in their own way and every situation is different. Some break down when the family member announce the diagnoses, some goes quiet. The main thing that people need to realize is that it always help to talk about their feelings about the possibility of losing a family member.
The anger of the fact that this disease can hit a loved one is great as soon as the news is made public. The anger will soon set over to support for the sufferer. Most families are brought together by this disease and a few are so shattered that the notion of family does not exist afterwards.
The impact of families being scattered apart on the sufferer is the greatest as the support from the family unit is not there anymore when the going gets tough. Where the family that stay together will be there in the time of need. 
The sufferer need to talk to family and friends to make it easier for them to deal with the disease. 
Open communications regarding the disease is vital so that the family unit can come with terms with what is install for the person suffering the disease. They need to know what effects the treatments would have. 
It is always advisable to get to know as much as possible about your family members particular cancer as the treatment is different in every case. Some cancers are terminal while others are treated with a great success rate. Information is power to the family as well as the sufferer.