Ttc and family member with cancer

My husband and I have been trying to conceive for 3 months now, and we just got the devastating news that my father has non-hodgkins lymphoma. He is starting very aggressive chemo next week that will be followed by radiation. I am unsure if we should put ttc on hold while my father endures treatment. Has anyone else been in this situation? Would I be allowed to spend time with him while he does radiation, etc.?