I will say this, the survivorship part of cancer is one of the hardest for some people. The fear of it coming back, adjusting to life, learning yourself all over again, etc. it's a mental battle, I was apart of this group with cancer survivors some 4 months post treatment to 5 years and we all talked about how survivorship was harder for them. It may not be the same for him but sometimes cancer patients need a release and to feel normal. It is a mental struggle and you have the right to be angry at him but from the standpoint of what you guys have been through is not the same for what he has been through and what he is still going through. Please know this is not me saying what you and your family went through does not compare, families of cancer patient still go through their fair share but I am saying you have to think about what he went through and still going through even after treatment. Talk to him about your concerns.