sorry to hear that, just spent the last 4 years living with this, with a wife who must be a similar age as i have 2 young children also, while my experience has a sad end – its important that he understands that there are plenty of treatments that will hopefully cure, and there are alot of people in remission (get this across as they may feel they have just been given a death sentance, thit is not the case)- his wife is young and fit and so she will be able to endure the treatment.
He just needs to know you are there for him, keep talking, let them know you love them, and when the initial shock wears off – keep encouraging them to live life, they must not stop doing things.
Please feel free to drop an email / get him to, db004u0093@blueyonder.co.uk
good luck – Dave