My close friend was diagnosed with breast cancer about 3 years ago. She went through chemo and had to undergo a double mastectomy, but thankfully now she is healthy and cancer-free. One piece of advice I can give you is to be a good listener. You can show your friend that you accept how he feels, which in turn may make him more comfortable about talking openly with you as he normally does and it will be less awkward for you. Make sure that when you visit to set aside time to focus on him and not other distractions. Also make sure you respect his wishes. Some days he might want to talk about it, other days he might want to focus on other things, and that’s where you come in. Even though this is a serious and stressful time for everyone, know that it’s okay to laugh and tell jokes. One thing my friend stressed to everyone was that she didn’t want people around her to pity her and talk about her cancer 24/7. She wanted people to have fun, act how they normally acted and not focus on her illness. With that said, I really hope everything works out for your friend. You are doing a lot already by being there for him during this difficult and scary time. Take care.