Does anyone know anything about skin cancer?

I just found out my brother has melanoma skin cancer. 3 spots on his back. He doesn’t know what stage it is in yet, or he just doesn’t want to say because he hates attention and doesn’t want the family calling him about it. He likes his peace. Me and my brother are very close, though, so he did tell me and our mother about it. I don’t know if my other siblings know, but I don’t want to say anything out of respect for his privacy. He’s a veteran who was medically discharged due to a spinal injury after 3 deployments in Iraq and has PTSD from that. He just gets stressed out very easily, and doesn’t exactly get along with the rest of our family. It would be wrong to mention it to the family. He has surgery to remove the spots and have them tested on Tuesday. He’s only 36. But my brother is like a father to me. Our dad is a complete asshole, to put it lightly. My brother has taken me in more than once growing up and has always been a major part of my support system. I’m just not sure how concerned I need to be about his cancer and I don’t want to push him for information esp if he doesn’t have a lot of info about it yet. It’s a hard pill to swallow.