I knew he was hiding something 😭😭😭😭

My boyfriend of one year (he's 18, I'm 20) has been very distant from me. He's always going to the doctor and when we are together he doesn't kiss or hug me or have sex. He just stares off. We rarely hang out now because he's always at the doctor. Well he texted me last night saying "I need to tell you something" but he wanted it to be in person. I went over to his house. His mom let me in and I went to his room. I sat on his bed and he was in tears. He said "I'm gonna tell you something. Just promise to be calm". I said okay and he says "I have cancer..." I thought this was a sick joke but I watched his tears fall. He has stage 3 lung cancer. I started crying and he laugh cried and said "You were supposed to stay calm". We hugged each other. He said "You're so unlucky. You're gonna have a bald boyfriend". I told him to quit joking. He said he didn't know how to tell me. And it's been hard. I said I wish he told me sooner so I could support him. He's starting chemo. Idk what to do... I love him so much .. are their good chances of surviving stage 3...