Hi to all

Welcome, but I wonder if you are in the right group - was it stomach cancer or bladder cancer diagnosed? If it is bladder, he is likely to be heading for a 'TURBT' op, which will remove as much as possible of the tumour and do a biopsy to determine what treatment is most appropriate. If caught early, BC is very treatable.

Telling children depends on their ages and ability to understand. I think Macmillan has some info about talking to children. You may not need to say anything at this stage, perhaps wait until you know a bit more. Best wishes.